I have composed a Fabric heavily moded mod pack that crashes on using the portal to Caving Dimension. All of your other portals worked fine.

I'm posting the server log, including the error log at the end.

Can you please spot what makes the issue?

Thanks for the help.

[17:20:52] [Server thread/FATAL]: Error executing task on Server
net.minecraft.class_148: Exception generating new chunk
at net.minecraft.class_1297.method_5784(class_1297.java:669) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_3244.method_12063(class_3244.java:897) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_2828.method_12272(class_2828.java:122) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_2828$class_2829.method_11054(class_2828.java:56) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_2600.method_11072(class_2600.java:21) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_3738.run(class_3738.java:18) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_1255.method_18859(class_1255.java:144) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_4093.method_18859(class_4093.java:23) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.server.MinecraftServer.method_24306(MinecraftServer.java:761) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.server.MinecraftServer.method_18859(MinecraftServer.java:155) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_1255.method_16075(class_1255.java:118) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.server.MinecraftServer.method_20415(MinecraftServer.java:743) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.server.MinecraftServer.method_16075(MinecraftServer.java:737) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_1255.method_18857(class_1255.java:127) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.server.MinecraftServer.method_16208(MinecraftServer.java:722) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.server.MinecraftServer.method_29741(MinecraftServer.java:674) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.server.MinecraftServer.method_29739(MinecraftServer.java:257) ~[intermediary-minecraft-1.16.5-client.jar:?]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_301]
Caused by: java.lang.IllegalArgumentException: bound must be positive
at java.util.Random.nextInt(Unknown Source) ~[?:1.8.0_301]
at net.minecraft.class_3785.method_16631(class_3785.java:131) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_3778.method_30419(class_3778.java:266) ~[intermediary-minecraft-1.16.5-client.jar:?]
at com.telepathicgrunt.repurposedstructures.world.structures.BuriableStructure$Start.init(BuriableStructure.java:63) ~[repurposed_structures-1.16.5-1.11.6-fabric.jar:?]
at com.telepathicgrunt.repurposedstructures.world.structures.BuriableStructure$Start.method_16655(BuriableStructure.java:54) ~[repurposed_structures-1.16.5-1.11.6-fabric.jar:?]
at net.minecraft.class_3195.method_28657(class_3195.java:261) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_5312.method_28622(class_5312.java:35) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_2794.method_28508(class_2794.java:278) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_2794.method_16129(class_2794.java:267) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_2806.method_16556(class_2806.java:51) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_2806.method_12154(class_2806.java:219) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_3898.method_17225(class_3898.java:568) ~[intermediary-minecraft-1.16.5-client.jar:?]
at com.mojang.datafixers.util.Either$Left.map(Either.java:38) ~[datafixerupper-4.0.26.jar:?]
at net.minecraft.class_3898.method_17224(class_3898.java:562) ~[intermediary-minecraft-1.16.5-client.jar:?]
at java.util.concurrent.CompletableFuture.uniCompose(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.CompletableFuture$UniCompose.tryFire(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.CompletableFuture$Completion.run(Unknown Source) ~[?:1.8.0_301]
at net.minecraft.class_3900.method_17634(class_3900.java:58) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_3846.method_16907(class_3846.java:94) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_3846.method_16900(class_3846.java:137) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_3846.run(class_3846.java:105) ~[intermediary-minecraft-1.16.5-client.jar:?]
at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.ForkJoinTask.doExec(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source) ~[?:1.8.0_301]
[17:20:52] [Server thread/ERROR]: Encountered an unexpected exception
java.util.concurrent.CompletionException: net.minecraft.class_148: Exception generating new chunk
at java.util.concurrent.CompletableFuture.encodeThrowable(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.CompletableFuture.completeThrowable(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.CompletableFuture.uniCompose(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.CompletableFuture$UniCompose.tryFire(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.CompletableFuture$Completion.run(Unknown Source) ~[?:1.8.0_301]
at net.minecraft.class_3900.method_17634(class_3900.java:58) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_3846.method_16907(class_3846.java:94) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_3846.method_16900(class_3846.java:137) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_3846.run(class_3846.java:105) ~[intermediary-minecraft-1.16.5-client.jar:?]
at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.ForkJoinTask.doExec(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source) ~[?:1.8.0_301]
at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source) ~[?:1.8.0_301]
Caused by: net.minecraft.class_148: Exception generating new chunk
at net.minecraft.class_3898.method_17225(class_3898.java:579) ~[intermediary-minecraft-1.16.5-client.jar:?]
at com.mojang.datafixers.util.Either$Left.map(Either.java:38) ~[datafixerupper-4.0.26.jar:?]
at net.minecraft.class_3898.method_17224(class_3898.java:562) ~[intermediary-minecraft-1.16.5-client.jar:?]
... 12 more
Caused by: java.lang.IllegalArgumentException: bound must be positive
at java.util.Random.nextInt(Unknown Source) ~[?:1.8.0_301]
at net.minecraft.class_3785.method_16631(class_3785.java:131) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_3778.method_30419(class_3778.java:266) ~[intermediary-minecraft-1.16.5-client.jar:?]
at com.telepathicgrunt.repurposedstructures.world.structures.BuriableStructure$Start.init(BuriableStructure.java:63) ~[repurposed_structures-1.16.5-1.11.6-fabric.jar:?]
at com.telepathicgrunt.repurposedstructures.world.structures.BuriableStructure$Start.method_16655(BuriableStructure.java:54) ~[repurposed_structures-1.16.5-1.11.6-fabric.jar:?]
at net.minecraft.class_3195.method_28657(class_3195.java:261) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_5312.method_28622(class_5312.java:35) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_2794.method_28508(class_2794.java:278) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_2794.method_16129(class_2794.java:267) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_2806.method_16556(class_2806.java:51) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_2806.method_12154(class_2806.java:219) ~[intermediary-minecraft-1.16.5-client.jar:?]
at net.minecraft.class_3898.method_17225(class_3898.java:568) ~[intermediary-minecraft-1.16.5-client.jar:?]
at com.mojang.datafixers.util.Either$Left.map(Either.java:38) ~[datafixerupper-4.0.26.jar:?]
at net.minecraft.class_3898.method_17224(class_3898.java:562) ~[intermediary-minecraft-1.16.5-client.jar:?]
... 12 more
[17:20:52] [Server thread/ERROR]: This crash report has been saved to: C:\Users\Jimmy\Desktop\MultiMC\instances\EXPLORER 1.16.5 fabric.minecraft\crash-reports\crash-2021-11-28_17.20.52-server.txt
[17:20:52] [Server thread/INFO]: Stopping server
[17:20:52] [Server thread/INFO]: Saving players
---- Minecraft Crash Report ----
// Uh... Did I do that?

Time: 11/28/21 5:20 PM
Description: Exception in server tick loop

java.util.concurrent.CompletionException: net.minecraft.class_148: Exception generating new chunk
at java.util.concurrent.CompletableFuture.encodeThrowable(Unknown Source)
at java.util.concurrent.CompletableFuture.completeThrowable(Unknown Source)
at java.util.concurrent.CompletableFuture.uniCompose(Unknown Source)
at java.util.concurrent.CompletableFuture$UniCompose.tryFire(Unknown Source)
at java.util.concurrent.CompletableFuture$Completion.run(Unknown Source)
at net.minecraft.class_3900.method_17634(class_3900.java:58)
at net.minecraft.class_3846.method_16907(class_3846.java:94)
at net.minecraft.class_3846.method_16900(class_3846.java:137)
at net.minecraft.class_3846.run(class_3846.java:105)
at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(Unknown Source)
at java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source)
at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)
Caused by: net.minecraft.class_148: Exception generating new chunk
at net.minecraft.class_3898.method_17225(class_3898.java:579)
at com.mojang.datafixers.util.Either$Left.map(Either.java:38)
at net.minecraft.class_3898.method_17224(class_3898.java:562)
... 12 more
Caused by: java.lang.IllegalArgumentException: bound must be positive
at java.util.Random.nextInt(Unknown Source)
at net.minecraft.class_3785.method_16631(class_3785.java:131)
at net.minecraft.class_3778.method_30419(class_3778.java:266)
at com.telepathicgrunt.repurposedstructures.world.structures.BuriableStructure$Start.init(BuriableStructure.java:63)
at com.telepathicgrunt.repurposedstructures.world.structures.BuriableStructure$Start.method_16655(BuriableStructure.java:54)
at net.minecraft.class_3195.method_28657(class_3195.java:261)
at net.minecraft.class_5312.method_28622(class_5312.java:35)
at net.minecraft.class_2794.method_28508(class_2794.java:278)
at net.minecraft.class_2794.method_16129(class_2794.java:267)
at net.minecraft.class_2806.method_16556(class_2806.java:51)
at net.minecraft.class_2806.method_12154(class_2806.java:219)
at net.minecraft.class_3898.method_17225(class_3898.java:568)
... 14 more

A detailed walkthrough of the error, its code path and all known details is as follows:

-- System Details --
Details:
Minecraft Version: 1.16.5
Minecraft Version ID: 1.16.5
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_301, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 4007229568 bytes (3821 MB) / 5711069184 bytes (5446 MB) up to 5711069184 bytes (5446 MB)
CPUs: 4
JVM Flags: 3 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xms4096m -Xmx6016m
Fabric Mods:
additionalbars: Additional Bars 2.0.4
advancednbttooltip: Advanced NBT Tooltips 1.6.0+build.3-1.16.5
advancements-enlarger: Advancements Enlarger 0.2.3
advdebug: Advancements Debug 2.3.0
alaskanativecraft: Alaska Native Craft 1.2.2
angerable-patch: Angerable Patch 1.1.0-1.16.4
antiqueatlas: Antique Atlas 6.1.0-fabric-mc1.16.5
anvilrestoration-fabric: Anvil Restoration (Fabric) 1.1
appleskin: AppleSkin mc1.16.4-2.2.0
aqupdcaracal: Caracal mob 1.16-1.3.2
aqupdgrizzly: Grizzly Bear mob 1.16-1.2.0
arcana2plus: Arcana ++ 0.0.3+1.16-alpha
architectury: Architectury 1.24.35
atmosfera: Atmosfera 1.4.2+mc1.16.5
audiooutput: AudioOutput 0.0.3
autoconfig1u: Auto Config v1 Updated 3.3.1
axesareweapons: Axes Are Weapons 1.5.1
bambootweaks: Bamboo Tweaks 2.0.5
bannerpp: Banner++ 2.0.3-snapshot+mc.1.16.2-rc1
bclib: BCLib 0.1.45
beenfo: Beenfo 1.16.5-fabric0.30.0-1.3.2
betterbiomeblend: Better Biome Blend 1.16.4-1.2.9-fabric
bettercaves: YUNG's Better Caves 1.16.5-1.2
betterdroppeditems: Better Dropped Items 1.2.4-1.16.2
betterend: Better End 0.9.8.5-pre
bettermineshafts: YUNG's Better Mineshafts 1.16.4-1.0.2
bettermounthud: Better Mount HUD 1.0.1
betternether: Better Nether 5.0.7
betterstones: Better Stones 0.0.4
betterstrongholds: YUNG's Better Strongholds 1.16.5-1.1.1
betterthanmending: BetterThanMending 1.3.0
biomemakeover: Biome Makeover 1.16.5-1.3.8
blue_endless_jankson: jankson 1.2.1
blur: Blur (Fabric) 2.1.0
bowinfinityfix: Bow Infinity Fix rv9
bundlesplus: bundles plus 0.2.1
byg: BYG 1.3.5
cameraoverhaul: Camera Overhaul 1.0.1-fabric-1.16
can-i-mine-this-block: cAn i MiNe thIS bLOCk? 1.0.2
candlebackport: Candle Backport 1.0
cardinal-components: Cardinal Components API 2.8.3
cardinal-components-base: Cardinal Components API (base) 2.8.3
cardinal-components-block: Cardinal Components API (blocks) 2.8.3
cardinal-components-chunk: Cardinal Components API (chunks) 2.8.3
cardinal-components-entity: Cardinal Components API (entities) 2.8.3
cardinal-components-item: Cardinal Components API (items) 2.8.3
cardinal-components-level: Cardinal Components API (world saves) 2.8.3
cardinal-components-scoreboard: Cardinal Components API (scoreboard) 2.8.3
cardinal-components-util: Cardinal Components API (utilities) 2.8.3
cardinal-components-world: Cardinal Components API (worlds) 2.8.3
castle_dungeons: Castle Dungeons 2.6
cavebiomes: Cave Biomes 0.6.2
cem: Custom Entity Models 0.1.3
cheeky-monkeys: Cheeky Monkeys 0.3.0-alpha
chicken_nerf: Chicken Nerf 1.0.5+MC1.16.2-1.16.5
chickensshed: ChickensShed 1.16.5-1.0.0
cleancut: CleanCut mc1.16-2.1-fabric
clear-skies: Clear Skies 1.5.57
cloth-basic-math: Cloth Basic Math 0.5.1
cloth-client-events-v0: Cloth Client Events v0 1.5.47
cloth-config2: Cloth Config v4 4.11.26
collective-fabric: Collective (Fabric) 3.0
colorfulcut: Colorful Cut 1.0.0
colormatic: Colormatic 2.2.9+mc.1.16.5
com_electronwill_night-config_core: core 3.6.2
com_electronwill_night-config_toml: toml 3.6.2
com_moandjiezana_toml_toml4j: toml4j 0.7.2
companion_bats: Companion Bats 1.15.2
complete_bone_meal: Complete Bone Meal 1.1.0
completeconfig: CompleteConfig 0.17.1
couplings: Couplings 1.3.3
crowdin-translate: CrowdinTranslate 1.3+1.16
ctm: ConnectedTexturesMod for Fabric 0.5.1+1.16
cullleaves: Cull Leaves 2.1.0
customportalapi: Custom Portals 0.0.1-beta32-1.16
customskinloader: CustomSkinLoader 14.13-SNAPSHOT-278
customsplashscreen: Custom Splash Screen 1.0.0
cyclepaintings-fabric: Cycle Paintings (Fabric) 2.1
damagetilt: Damage Tilt 1.16-fabric-0.1.2
damagetint: Damage tint 1.1.0
darkness: True Darkness 1.6.58
darkpaintings: DarkPaintings 3.0.2
deadlydaggers: DeadlyDaggers 1.0-1.16.5
deerorigin: A Deer Origin 2.0
despawningeggshatch-fabric: Despawning Eggs Hatch (Fabric) 2.3
detailab: Detail Armor Bar 2.6.1+1.16.5-fabric
direbats: Direbats 1.1.1+1.16.5-fabric
disable_custom_worlds_advice: Disable Custom Worlds Advice 1.3
dual_riders: DualRiders 1.0.5
dynamicfps: Dynamic FPS 2.0.2
dynamo_api: Dynamo API 1.0.0+1.16
earthtojavamobs: Earth2Java 1.7.1+1.16.4
elhuevo: El Huevo 1.16.5-1.0.0
enchantedtooltips: Enchanted ToolTips 1.3.5-1.16
enchantment_lore: EnchantmentLore 1.1.1+MC1.16.1-1.16.5
endlessoceans: Endless Oceans 1.0.5
engilib: EngiLib 1.0.0+1.16.4
enhanced_attack_indicator: Enhanced Attack Indicator 1.0.1
entitybanners: Entity Banners 1.0-BETA
entityculling: EntityCulling-Fabric 1.3.0
equip: EquipZ 1.6.2
expanded_armor_enchanting: Expanded Armor Enchanting 1.0.0
expanded_trident_enchanting: Expanded Trident Enchanting 1.0.0
expanded_weapon_enchanting: Expanded Weapon Enchanting 1.0.0
extrakeybinds: CyaConnors Extra Origins Keybinds 1.16.5-0.1.2
extramaterials: Extra Materials 1.0.0
fabric: Fabric API 0.42.0+1.16
fabric-api-base: Fabric API Base 0.4.0+3cc0f0907d
fabric-api-lookup-api-v1: Fabric API Lookup API (v1) 1.3.1+3cc0f0907d
fabric-biome-api-v1: Fabric Biome API (v1) 3.1.13+3cc0f0907d
fabric-blockrenderlayer-v1: Fabric BlockRenderLayer Registration (v1) 1.1.6+3cc0f0907d
fabric-command-api-v1: Fabric Command API (v1) 1.1.3+3cc0f0907d
fabric-commands-v0: Fabric Commands (v0) 0.2.3+3cc0f0907d
fabric-containers-v0: Fabric Containers (v0) 0.1.12+3cc0f0907d
fabric-content-registries-v0: Fabric Content Registries (v0) 0.2.5+3cc0f0907d
fabric-crash-report-info-v1: Fabric Crash Report Info (v1) 0.1.4+3cc0f0907d
fabric-diagonal-panes: Fabric Diagonal Panes 0.4.0
fabric-dimensions-v1: Fabric Dimensions API (v1) 2.0.8+3cc0f0907d
fabric-entity-events-v1: Fabric Entity Events (v1) 1.2.4+3cc0f0907d
fabric-events-interaction-v0: Fabric Events Interaction (v0) 0.4.5+3cc0f0907d
fabric-events-lifecycle-v0: Fabric Events Lifecycle (v0) 0.2.2+3cc0f0907d
fabric-game-rule-api-v1: Fabric Game Rule API (v1) 1.0.7+3cc0f0907d
fabric-item-api-v1: Fabric Item API (v1) 1.2.2+3cc0f0907d
fabric-item-groups-v0: Fabric Item Groups (v0) 0.3.1+3cc0f0907d
fabric-key-binding-api-v1: Fabric Key Binding API (v1) 1.0.5+3cc0f0907d
fabric-keybindings-v0: Fabric Key Bindings (v0) 0.2.2+3cc0f0907d
fabric-language-kotlin: Fabric Language Kotlin 1.6.1+kotlin.1.5.10
fabric-lifecycle-events-v1: Fabric Lifecycle Events (v1) 1.2.2+3cc0f0907d
fabric-loot-tables-v1: Fabric Loot Tables (v1) 1.0.3+3cc0f0907d
fabric-mining-levels-v0: Fabric Mining Levels (v0) 0.1.4+3cc0f0907d
fabric-models-v0: Fabric Models (v0) 0.3.1+3cc0f0907d
fabric-networking-api-v1: Fabric Networking API (v1) 1.0.5+3cc0f0907d
fabric-networking-blockentity-v0: Fabric Networking Block Entity (v0) 0.2.9+3cc0f0907d
fabric-networking-v0: Fabric Networking (v0) 0.3.3+3cc0f0907d
fabric-object-builder-api-v1: Fabric Object Builder API (v1) 1.9.6+3cc0f0907d
fabric-object-builders-v0: Fabric Object Builders (v0) 0.7.3+3cc0f0907d
fabric-particles-v1: Fabric Particles (v1) 0.2.5+3cc0f0907d
fabric-permissions-api-v0: fabric-permissions-api 0.1-SNAPSHOT
fabric-registry-sync-v0: Fabric Registry Sync (v0) 0.7.6+3cc0f0907d
fabric-renderer-api-v1: Fabric Renderer API (v1) 0.4.5+3cc0f0907d
fabric-renderer-indigo: Fabric Renderer - Indigo 0.4.5+3cc0f0907d
fabric-renderer-registries-v1: Fabric Renderer Registries (v1) 2.3.1+3cc0f0907d
fabric-rendering-data-attachment-v1: Fabric Rendering Data Attachment (v1) 0.1.6+3cc0f0907d
fabric-rendering-fluids-v1: Fabric Rendering Fluids (v1) 0.1.15+3cc0f0907d
fabric-rendering-v0: Fabric Rendering (v0) 1.1.3+3cc0f0907d
fabric-rendering-v1: Fabric Rendering (v1) 1.6.1+3cc0f0907d
fabric-resource-loader-v0: Fabric Resource Loader (v0) 0.4.8+3cc0f0907d
fabric-screen-api-v1: Fabric Screen API (v1) 1.0.1+3cc0f0907d
fabric-screen-handler-api-v1: Fabric Screen Handler API (v1) 1.1.6+3cc0f0907d
fabric-structure-api-v1: Fabric Structure API (v1) 1.1.12+3cc0f0907d
fabric-tag-extensions-v0: Fabric Tag Extensions (v0) 1.1.2+3cc0f0907d
fabric-textures-v0: Fabric Textures (v0) 1.0.7+3cc0f0907d
fabric-tool-attribute-api-v1: Fabric Tool Attribute API (v1) 1.2.8+3cc0f0907d
fabric-transfer-api-v1: Fabric Transfer API (v1) 1.5.0+3cc0f0907d
fabricloader: Fabric Loader 0.11.7
fabricshieldlib: Fabric Shield Lib 1.4.4-1.16.5
fabrishot: Fabrishot 1.4.0
fallflyinglib: FallFlyingLib 2.0.4
fallingleaves: Falling Leaves 1.6.0+1.16.5
fastchest: FastChest 1.2+1.16
ferritecore: FerriteCore 2.1.0
fiber: fiber 0.23.0-2
fixedanvilrepaircost-fabric: Fixed Anvil Repair Cost (Fabric) 1.6
flamingo_ooo: Flamingo, oh, oh, oh... 1.0.4-MC1.16.3-fabric
ftblibrary: FTB Library 1605.3.4-build.87
ftbquests: FTB Quests 1605.3.5-build.72
ftbteams: FTB Teams 1605.2.3-build.40
fullturtlearmor: Full Turtle Armor 1.0.1
gbfabrictools: GBfabrictools 1.3.2+1.16.4
geckolib3: Geckolib 3.0.58
gentlefawn: GentleFawn 1.1.4-MC1.16.5-fabric
glassential: Glassential 1.16.4-1.1.5
go-fish: Go Fish 1.2.3-beta-1.16.5
goat: Goat origin 1.0.0
gravestones: Gravestones v1.9
grindenchantments: Grind Enchantments 1.1.3+1.16.3
healthblast: Health Blast 1.0.0
horseinfo: Horse Info 0.2.2-1.16.1
hydrogen: Hydrogen 0.2
indium: Indium 1.0.0+mc1.16.5
inmis: Inmis 2.2.1-1.16.5
inventorysorter: Inventory Sorter 1.7.9-1.16
invmove: InvMove 1.16-0.1.0
iris: Iris 1.1.2+build.4
itemfilters: Item Filters 1605.2.5-build.9
itemmodelfix: Item Model Fix 1.0.2+1.16
jankson: Jankson 3.0.1+j1.2.0
java: Java HotSpot(TM) 64-Bit Server VM 8
jumpoverfences: JumpOverFences 1.16-0.0.3
kiln: Kiln 1.1.1+1.16.5
krypton: Krypton 0.1.2
kubejs: KubeJS 1605.3.19-build.180
kyrptconfig: Kytpt Config 1.1.8-1.16
lambdabettergrass: LambdaBetterGrass 1.0.3+1.16
lambdynlights: LambDynamicLights 1.3.4+1.16
lapisreserve: Lapis Reserve 1.0.7
lazydfu: LazyDFU 0.1.2
libblockattributes: LibBlockAttributes 0.8.8
libblockattributes_core: LibBlockAttributes (Core) 0.8.8
libblockattributes_fluids: LibBlockAttributes (Fluids) 0.8.8
libblockattributes_items: LibBlockAttributes (Items) 0.8.8
libgui: LibGui 3.3.5+1.16.5
libmultipart: LibMultiPart 0.5.0
libmultipart_deps_container: LibMultiPart (Dependency Container) 0.5.0
libnetworkstack: Lib Network Stack 0.4.7
lock_minecart_view: Better minecart rotation 1.2.1
magic_mirror: Magic Mirror 1.2.1
maybe-data: Maybe data 1.0.0-1.16.2
mcf-easyfeed: Easy Feed and Breed 1.3.0
mcwifipnp: LAN World Plug-n-Play 1.5.3
mechanicaltech: Mechanical Tech 0.3.0+1.16
megane: megane 4.1.4
megane-base: megane-base 4.1.4
megane-lib-block-attributes: megane-lib-block-attributes 4.1.4+0.8.7
megane-runtime: megane-runtime 4.1.4
megane-team-reborn-energy: megane-team-reborn-energy 4.1.4+0.1.0
megane-vanilla: megane-vanilla 4.1.4+1.16.5
minecraft: Minecraft 1.16.5
minegate-moreblocks: MineGate · MoreBlocks 1.1.3
mining_dims: Mining Dimensions 1.0.5
modmenu: Mod Menu 1.16.22
moreberries: More Berries 1.3.6
morevillagers-fabric: MoreVillagersFabric 1.4.1-SNAPSHOT
mostructures: Mo' Structures 1.2.0-1.16.5
nbtcrafting: NBT Crafting 2.1.0+mc1.16.4
new_buckets: New Buckets 1.0.1
no_fog: No Fog 1.0.2-beta.1+1.16.2
notes: Notes 1.0.4
npcvariety: NPC Variety 1.2.4
okzoomer: Ok Zoomer 4.0.1+1.16.2
omega-config: OmegaConfig 1.0.4
openloader: OpenLoader 1.0.2
org_aperlambda_lambdajcommon: lambdajcommon 1.8.1
org_jetbrains_kotlin_kotlin-reflect: kotlin-reflect 1.5.10
org_jetbrains_kotlin_kotlin-stdlib: kotlin-stdlib 1.5.10
org_jetbrains_kotlin_kotlin-stdlib-jdk7: kotlin-stdlib-jdk7 1.5.10
org_jetbrains_kotlin_kotlin-stdlib-jdk8: kotlin-stdlib-jdk8 1.5.10
org_jetbrains_kotlinx_kotlinx-coroutines-core-jvm: kotlinx-coroutines-core-jvm 1.5.0
org_jetbrains_kotlinx_kotlinx-coroutines-jdk8: kotlinx-coroutines-jdk8 1.5.0
org_jetbrains_kotlinx_kotlinx-serialization-core-jvm: kotlinx-serialization-core-jvm 1.2.1
org_jetbrains_kotlinx_kotlinx-serialization-json-jvm: kotlinx-serialization-json-jvm 1.2.1
origins: Origins 0.7.3
origins-classes: Origins: Classes 1.1.1
parakeetmod: The Parakeet Mod 1.16.3-1.0.6
passable-leaves: Passable Leaves 1.2.3
phosphor: Phosphor 0.7.2+build.12
playerabilitylib: Pal 1.2.2
pling: Pling 1.3.0
polymorph: Polymorph 0.0.13-1.16.5
potiondescriptions: Potion Descriptions fabric-1.1
raisedclouds: Raised Clouds 1.0.0
reach-entity-attributes: Reach Entity Attributes 1.1.1
reborncore: Reborn Core 4.7.2+build.134
replanter: Replanter 1.1.0
repurposed_structures: Repurposed Structures 1.16.5-1.11.6-fabric
reroll: Reroll 1.2.1-1.16.5
rfmagnet: RF Magnet 1.0.0
rhino: Rhino 1605.1.5-build.75
riverredux: River Redux 0.1.6
roughlyenoughitems: Roughly Enough Items 5.12.248
roughlyenoughitems-api: REI (API) 5.12.248
roughlyenoughitems-default-plugin: REI (Default Plugin) 5.12.248
roughlyenoughitems-runtime: REI (Runtime) 5.12.248
rpgstats: RPGStats 4.0.5+1.16.5
rpgz: RPGZ 0.4.7
satin: Satin 1.5.1
savemystronghold: Save My Stronghold! 1.16.4-1.0
seasons: Fabric Seasons 1.2.0.1-BETA+1.16
sign_editor: Better Signs & Frames mc-1.16.5-0.7.0
skeletonhorsespawn-fabric: Skeleton Horse Spawn (Fabric) 1.9
slabstoblocks: SlabsToBlocks 1.0.0
smoothboot: Smooth Boot 1.16.5-1.6.0
snowy_leaves: Snowy Leaves 1.16.1-1.3.1
sodium: Sodium 0.2.0+IRIS4-build.4
spark: spark 1.6.0
spawnermod: Enhanced Mob Spawners 1.1.2
spruceui: SpruceUI 2.0.4+1.16
static-content: Static Content 1.0.1-1.16.2
staticdata: Static Data 1.1.2
stitchedsnow: Stiched Snow 1.0.1
stoneholm: Stoneholm 1.2.3
stonetotools: StoneToTools 1.0.0
taxfreelevels: Tax Free Levels 1.1
team_reborn_energy: Energy 0.1.1
terrarianslimes: Terrarian Slimes 1.1-BETA+1.16
tooltipfix: ToolTip Fix 1.0.2-1.16
toomanyorigins: TooManyOrigins 0.2.2.1
tridentfixer: Repairable Tridents 1.0.1
untitledduckmod: Untitled Duck Mod 0.2.2
vanilla_degus: Vanilla Degus 1.1.1
vanilla_parts: Vanilla Parts 1.1.4+1.16.3
villagernames: Villager Names 1.6.0
voyager: Voyager 1.0.0
waila: Hwyla 1.9.22
waystones: Waystones 2.0.1
wolveswitharmor: Wolves With Armor 1.5.4-1.16.5
woodenhoppers: Wooden Hoppers 1.0.0
xp_storage: XP Storage 1.4+1.16.5
yungsapi: YUNG's API 1.16.5-Fabric-9
Player Count: 1 / 8; [class_3222['Syrus'/250, l='ServerLevel[dddddd]', x=-249.88, y=75.00, z=237.24]]
Data Packs: vanilla, openloader/data/custom_vanilla_recipes_datapack, openloader/data/mechanicaltech_compatibility_datapack, Fabric Mods
Type: Integrated Server (map_client.txt)
Is Modded: Definitely; Client brand changed to 'fabric'
#@!@# Game crashed! Crash report saved to: #@!@# C:\Users\Jimmy\Desktop\MultiMC\instances\EXPLORER 1.16.5 fabric.minecraft\crash-reports\crash-2021-11-28_17.20.52-server.txt
AL lib: (EE) alc_cleanup: 1 device not closed
Process exited with code -1.

Added Caving Dim into dimension Exceptions of Repurposed Structures config as you suggested:

blacklistedDimensions = "the_bumblezone:the_bumblezone,the_aether:the_aether,mining_dims:caving_dim"

It didn't work on existing or new worlds.

1.16.5 Repurposed Structures is no longer maintained. Though the crash is caused by the start pool for one of the RS pyramids being nuked to empty. This is caused often by another mod adding properties unsafely to blocks and blowing up how vanilla minecraft parses my mod's json processor files. And that error cascades and nukes the pool file.

Remove mods that are adding properties to blocks until you find the culprit. From a quick look at the modlist, you have minegate on which is know for breaking worldgen json file due to adding properties unsafely.
MrFantiVideo/MineGate#5

Unfortunately, they did not switched to using Statement library and instead, opted for using config to disable their dangerous mixin that is incompatible with vanilla's worldgen json system.

SyrusTemplar: try removing the MineGate More Blocks to see if that clears it up or try the config options in that mod. If you want to keep More Blocks, then you will have to go without Mining Dims.

Also, my 1.16.5 mods will only get critical defect fixes and mod conflicts are generally not part of that. MY active effort is on 1.18 now.

I'm going ahead and closing this since there is nothing I can do about it anyway.

Oh, good to know, I guess I wasn't picking up on that. My Mining Dim is just trying to use everything defined for OverWorld and becomes a victim of the situation.

@kwpugh the issue isnt anything to do with mining dimension. it's a conflict between RS and MineGate where RS dies trying to generate its own structure. This crash would occur in overworld too if the user finds the pyramid that is crashing

You guys are great!
It was Minegate and all works well once removed.
I'm going to substitute Minegate cos Caving Dimension is mandatory for the pack.
Thanks for the help everyone! Keep up the good work!