I'm on litematica-fabric-1.16.4-0.0.0-dev.20210112.155314 and malLiB malilib-fabric-1.16.4-0.10.0-dev.21+arne.2

---- Minecraft Crash Report ----
// I bet Cylons wouldn't have this problem.

Time: 1/18/21 4:38 AM
Description: Unexpected error

java.lang.NullPointerException: Unexpected error
at fi.dy.masa.litematica.render.OverlayRenderer.updateBlockInfoLines(OverlayRenderer.java:623)
at fi.dy.masa.litematica.render.OverlayRenderer.renderBlockInfoLines(OverlayRenderer.java:500)
at fi.dy.masa.litematica.render.OverlayRenderer.renderHoverInfo(OverlayRenderer.java:482)
at fi.dy.masa.litematica.event.RenderHandler.onRenderGameOverlayPost(RenderHandler.java:51)
at fi.dy.masa.malilib.event.RenderEventHandler.onRenderGameOverlayPost(RenderEventHandler.java:63)
at net.minecraft.class_329.handler$zen000$onGameOverlayPost(class_329.java:1327)
at net.minecraft.class_329.method_1753(class_329.java:439)
at net.minecraft.class_757.method_3192(class_757.java:765)
at net.minecraft.class_310.method_1523(class_310.java:1048)
at net.minecraft.class_310.method_1514(class_310.java:681)
at net.minecraft.client.main.Main.main(Main.java:215)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:224)
at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:141)
at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:27)

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

-- Head --
Thread: Render thread
Stacktrace:
at fi.dy.masa.litematica.render.OverlayRenderer.updateBlockInfoLines(OverlayRenderer.java:623)
at fi.dy.masa.litematica.render.OverlayRenderer.renderBlockInfoLines(OverlayRenderer.java:500)
at fi.dy.masa.litematica.render.OverlayRenderer.renderHoverInfo(OverlayRenderer.java:482)
at fi.dy.masa.litematica.event.RenderHandler.onRenderGameOverlayPost(RenderHandler.java:51)
at fi.dy.masa.malilib.event.RenderEventHandler.onRenderGameOverlayPost(RenderEventHandler.java:63)
at net.minecraft.class_329.handler$zen000$onGameOverlayPost(class_329.java:1327)
at net.minecraft.class_329.method_1753(class_329.java:439)

-- Affected level --
Details:
All players: 1 total; [class_746['RadNotRed'/2, l='ClientLevel', x=-2718.37, y=4.00, z=227.87]]
Chunk stats: Client Chunk Cache: 2809, 627
Level dimension: minecraft:overworld
Level spawn location: World: (-2718,5,224), Chunk: (at 2,0,0 in -170,14; contains blocks -2720,0,224 to -2705,255,239), Region: (-6,0; contains chunks -192,0 to -161,31, blocks -3072,0,0 to -2561,255,511)
Level time: 202917 game time, 202917 day time
Server brand: fabric
Server type: Integrated singleplayer server
Stacktrace:
at net.minecraft.class_638.method_8538(class_638.java:617)
at net.minecraft.class_310.method_1587(class_310.java:2239)
at net.minecraft.class_310.method_1514(class_310.java:704)
at net.minecraft.client.main.Main.main(Main.java:215)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:224)
at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:141)
at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:27)

-- System Details --
Details:
Minecraft Version: 1.16.4
Minecraft Version ID: 1.16.4
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_51, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 5382370800 bytes (5133 MB) / 9395240960 bytes (8960 MB) up to 12884901888 bytes (12288 MB)
CPUs: 32
JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx12G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
Fabric Mods:
amecsapi: Amecs API 1.1.1+mc1.16-rc1
appleskin: AppleSkin 1.0.11
architectury: Architectury 1.3.81
artifice: Artifice 0.13.1+1.16.2-rc1
autoconfig1u: Auto Config v1 Updated 3.3.1
baritoe: Baritone 1.6.1
blur: Blur (Fabric) 2.0.0
borderlessmining: Borderless Mining 1.0.6+1.16.2
cloth-basic-math: Cloth Basic Math 0.5.1
cloth-client-events-v0: Cloth Client Events v0 1.4.9
cloth-config2: Cloth Config v4 4.8.3
com_moandjiezana_toml_toml4j: toml4j 0.7.2
dynamicfps: Dynamic FPS 2.0.0
fabric: Fabric API 0.29.3+1.16
fabric-api-base: Fabric API Base 0.2.0+ab87788d3a
fabric-biome-api-v1: Fabric Biome API (v1) 3.1.0+2e23b97c3a
fabric-blockrenderlayer-v1: Fabric BlockRenderLayer Registration (v1) 1.1.4+c6a8ea8995
fabric-command-api-v1: Fabric Command API (v1) 1.0.9+6a2618f53a
fabric-commands-v0: Fabric Commands (v0) 0.2.1+cbe9176f3a
fabric-containers-v0: Fabric Containers (v0) 0.1.9+a03e98793a
fabric-content-registries-v0: Fabric Content Registries (v0) 0.2.0+e77439c73a
fabric-crash-report-info-v1: Fabric Crash Report Info (v1) 0.1.2+b7f9825d3a
fabric-dimensions-v1: fabric-dimensions-v1 2.0.1+9a6c75813a
fabric-entity-events-v1: Fabric Entity Events (v1) 1.0.2+8004b36d3a
fabric-events-interaction-v0: Fabric Events Interaction (v0) 0.4.1+6a2618f53a
fabric-events-lifecycle-v0: Fabric Events Lifecycle (v0) 0.2.0+16acbe5b95
fabric-game-rule-api-v1: Fabric Game Rule API (v1) 1.0.5+cbe9176f3a
fabric-item-api-v1: Fabric Item API (v1) 1.2.0+6a2618f53a
fabric-item-groups-v0: Fabric Item Groups (v0) 0.2.2+cbe9176f3a
fabric-key-binding-api-v1: Fabric Key Binding API (v1) 1.0.1+730711c63a
fabric-keybindings-v0: Fabric Key Bindings (v0) 0.2.0+3fa9f7c595
fabric-lifecycle-events-v1: Fabric Lifecycle Events (v1) 1.2.0+74cc3b2095
fabric-loot-tables-v1: Fabric Loot Tables (v1) 1.0.1+6a2618f53a
fabric-mining-levels-v0: Fabric Mining Levels (v0) 0.1.2+b764ce9995
fabric-models-v0: Fabric Models (v0) 0.2.0+cbe9176f3a
fabric-networking-api-v1: Fabric Networking API (v1) 1.0.0+4358fbc63a
fabric-networking-blockentity-v0: Fabric Networking Block Entity (v0) 0.2.7+a03e98793a
fabric-networking-v0: Fabric Networking (v0) 0.3.1+2a4333d33a
fabric-object-builder-api-v1: Fabric Object Builder API (v1) 1.9.2+6a2618f53a
fabric-object-builders-v0: Fabric Object Builders (v0) 0.7.1+6a2618f53a
fabric-particles-v1: Fabric Particles (v1) 0.2.3+cbe9176f3a
fabric-registry-sync-v0: Fabric Registry Sync (v0) 0.7.3+be155ae23a
fabric-renderer-api-v1: Fabric Renderer API (v1) 0.4.0+cbe9176f3a
fabric-renderer-indigo: Fabric Renderer - Indigo 0.4.3+6a2618f53a
fabric-renderer-registries-v1: Fabric Renderer Registries (v1) 2.2.0+6a2618f53a
fabric-rendering-data-attachment-v1: Fabric Rendering Data Attachment (v1) 0.1.4+6a2618f53a
fabric-rendering-fluids-v1: Fabric Rendering Fluids (v1) 0.1.12+6a2618f53a
fabric-rendering-v0: Fabric Rendering (v0) 1.1.1+6a2618f53a
fabric-rendering-v1: Fabric Rendering (v1) 1.5.0+c26373133a
fabric-resource-loader-v0: Fabric Resource Loader (v0) 0.4.1+0d4d7e343a
fabric-screen-handler-api-v1: Fabric Screen Handler API (v1) 1.1.0+6a2618f53a
fabric-structure-api-v1: Fabric Structure API (v1) 1.1.3+cbe9176f3a
fabric-tag-extensions-v0: Fabric Tag Extensions (v0) 1.1.0+e77439c73a
fabric-textures-v0: Fabric Textures (v0) 1.0.5+6a2618f53a
fabric-tool-attribute-api-v1: Fabric Tool Attribute API (v1) 1.2.5+6a2618f53a
fabricloader: Fabric Loader 0.10.8
iamverysmart: I Am Very Smart 2.1.0+mc1.16.1
lightoverlay: Light Overlay 5.5.0
litematica: Litematica 0.0.0-dev.20210112.155314
malilib: MaLiLib 0.10.0-dev.21+arne.2
minecraft: Minecraft 1.16.4
mm: Manningham Mills 2.1
modmenu: Mod Menu 1.14.13+build.19
mousewheelie: Mouse Wheelie 1.6.2+mc1.16.4
optifabric: OptiFabric 1.8.16
org_codehaus_groovy_groovy: groovy 3.0.3
org_codehaus_groovy_groovy-jsr223: groovy-jsr223 3.0.3
perspectivemod: Perspective Mod Redux 0.0.5
phosphor: Phosphor 0.7.0+build.10
roughlyenoughitems: Roughly Enough Items 5.8.10
roughlyenoughitems-api: REI (API) 5.8.10
roughlyenoughitems-default-plugin: REI (Default Plugin) 5.8.10
roughlyenoughitems-runtime: REI (Runtime) 5.8.10
satin: Satin 1.5.1
slight-gui-modifications: 'Slight' GUI Modifications 1.6.1
smoothscrollingeverywhere: Smooth Scrolling Everywhere 3.0.3-unstable
tweed: Tweed API 3.0.0-beta.22
worldedit: WorldEdit 7.2.1+299386a
wurst: Wurst Client v7.10-MC1.16.4
xaerominimap: Xaero's Minimap 20.30.1
xaeroworldmap: Xaero's World Map 1.11.7
Launched Version: fabric-loader-0.10.8-1.16.4
Backend library: LWJGL version 3.2.2 build 10
Backend API: GeForce GTX 1070 Ti/PCIe/SSE2 GL version 4.6.0 NVIDIA 461.09, NVIDIA Corporation
GL Caps: Using framebuffer using OpenGL 3.0
Using VBOs: Yes
Is Modded: Definitely; Client brand changed to 'fabric'
Type: Client (map_client.txt)
Graphics mode: fancy
Resource Packs: vanilla, slightguimodifications:cts_textures, Fabric Mods, file/1.16.zip
Current Language: English (New Zealand)
CPU: 32x AMD Ryzen Threadripper 1950X 16-Core Processor
OptiFine Version: OptiFine_1.16.4_HD_U_G5
OptiFine Build: 20201106-171901
Render Distance Chunks: 24
Mipmaps: 4
Anisotropic Filtering: 1
Antialiasing: 0
Multitexture: false
Shaders: null
OpenGlVersion: 4.6.0 NVIDIA 461.09
OpenGlRenderer: GeForce GTX 1070 Ti/PCIe/SSE2
OpenGlVendor: NVIDIA Corporation
CpuCount: 32

-- OptiFabric --
Details:
OptiFine jar designed for: 1.16.4
OptiFine jar version: OptiFine_1.16.4_HD_U_G5
OptiFine jar status: Valid OptiFine installer
OptiFine remapped jar: C:\Users\cjrec\AppData\Roaming.minecraft.optifine\OptiFine_1.16.4_HD_U_G5\Optifine-mapped.jar
OptiFabric error:

This issue is also happening to me, although it seems to be crashing during a different method than the above commenter's crash.

---- Minecraft Crash Report ----
// Hi. I'm Minecraft, and I'm a crashaholic.

Time: 1/29/21 5:52 PM
Description: Unexpected error

java.lang.NullPointerException: Unexpected error
at fi.dy.masa.litematica.render.schematic.WorldRendererSchematic.setupTerrain(WorldRendererSchematic.java:218)
at fi.dy.masa.litematica.render.LitematicaRenderer.piecewisePrepareAndUpdate(LitematicaRenderer.java:321)
at net.minecraft.class_761.handler$zlm000$onPostSetupTerrain(class_761.java:6115)
at net.minecraft.class_761.method_3273(class_761.java:3171)
at net.minecraft.class_761.method_22710(class_761.java:1131)
at net.minecraft.class_757.method_3188(class_757.java:727)
at net.minecraft.class_757.method_3192(class_757.java:546)
at net.minecraft.class_310.method_1523(class_310.java:1048)
at net.minecraft.class_310.method_1514(class_310.java:681)
at net.minecraft.client.main.Main.main(Main.java:215)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:226)
at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:139)
at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:27)

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

-- Head --
Thread: Render thread
Stacktrace:
at fi.dy.masa.litematica.render.schematic.WorldRendererSchematic.setupTerrain(WorldRendererSchematic.java:218)
at fi.dy.masa.litematica.render.LitematicaRenderer.piecewisePrepareAndUpdate(LitematicaRenderer.java:321)
at net.minecraft.class_761.handler$zlm000$onPostSetupTerrain(class_761.java:6115)
at net.minecraft.class_761.method_3273(class_761.java:3171)
at net.minecraft.class_761.method_22710(class_761.java:1131)
at net.minecraft.class_757.method_3188(class_757.java:727)

-- Affected level --
Details:
All players: 1 total; [class_746['realsinse420'/69998, l='ClientLevel', x=29999695.25, y=64.00, z=29999868.61]]
Chunk stats: SodiumChunkCache: 441
Level dimension: minecraft:overworld
Level spawn location: World: (192,71,-64), Chunk: (at 0,4,0 in 12,-4; contains blocks 192,0,-64 to 207,255,-49), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
Level time: 30472189 game time, 1000 day time
Server brand: fabric
Server type: Non-integrated multiplayer server
Stacktrace:
at net.minecraft.class_638.method_8538(class_638.java:449)
at net.minecraft.class_310.method_1587(class_310.java:2239)
at net.minecraft.class_310.method_1514(class_310.java:704)
at net.minecraft.client.main.Main.main(Main.java:215)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:226)
at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:139)
at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:27)

-- System Details --
Details:
Minecraft Version: 1.16.4
Minecraft Version ID: 1.16.4
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_51, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 873371624 bytes (832 MB) / 2046820352 bytes (1952 MB) up to 2147483648 bytes (2048 MB)
CPUs: 4
JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
Fabric Mods:
fabric: Fabric API 0.29.3+1.16
fabric-api-base: Fabric API Base 0.2.0+ab87788d3a
fabric-biome-api-v1: Fabric Biome API (v1) 3.1.0+2e23b97c3a
fabric-blockrenderlayer-v1: Fabric BlockRenderLayer Registration (v1) 1.1.4+6a2618f53a
fabric-command-api-v1: Fabric Command API (v1) 1.0.9+6a2618f53a
fabric-commands-v0: Fabric Commands (v0) 0.2.1+cbe9176f3a
fabric-containers-v0: Fabric Containers (v0) 0.1.9+a03e98793a
fabric-content-registries-v0: Fabric Content Registries (v0) 0.2.0+e77439c73a
fabric-crash-report-info-v1: Fabric Crash Report Info (v1) 0.1.2+b7f9825d3a
fabric-dimensions-v1: fabric-dimensions-v1 2.0.1+9a6c75813a
fabric-entity-events-v1: Fabric Entity Events (v1) 1.0.2+8004b36d3a
fabric-events-interaction-v0: Fabric Events Interaction (v0) 0.4.1+6a2618f53a
fabric-events-lifecycle-v0: Fabric Events Lifecycle (v0) 0.2.0+6a2618f53a
fabric-game-rule-api-v1: Fabric Game Rule API (v1) 1.0.5+cbe9176f3a
fabric-item-api-v1: Fabric Item API (v1) 1.2.0+6a2618f53a
fabric-item-groups-v0: Fabric Item Groups (v0) 0.2.2+cbe9176f3a
fabric-key-binding-api-v1: Fabric Key Binding API (v1) 1.0.1+730711c63a
fabric-keybindings-v0: Fabric Key Bindings (v0) 0.2.0+6a2618f53a
fabric-lifecycle-events-v1: Fabric Lifecycle Events (v1) 1.2.0+ffb68a873a
fabric-loot-tables-v1: Fabric Loot Tables (v1) 1.0.1+6a2618f53a
fabric-mining-levels-v0: Fabric Mining Levels (v0) 0.1.2+6a2618f53a
fabric-models-v0: Fabric Models (v0) 0.2.0+cbe9176f3a
fabric-networking-api-v1: Fabric Networking API (v1) 1.0.0+4358fbc63a
fabric-networking-blockentity-v0: Fabric Networking Block Entity (v0) 0.2.7+a03e98793a
fabric-networking-v0: Fabric Networking (v0) 0.3.1+2a4333d33a
fabric-object-builder-api-v1: Fabric Object Builder API (v1) 1.9.2+6a2618f53a
fabric-object-builders-v0: Fabric Object Builders (v0) 0.7.1+6a2618f53a
fabric-particles-v1: Fabric Particles (v1) 0.2.3+cbe9176f3a
fabric-registry-sync-v0: Fabric Registry Sync (v0) 0.7.3+be155ae23a
fabric-renderer-api-v1: Fabric Renderer API (v1) 0.4.0+cbe9176f3a
fabric-renderer-indigo: Fabric Renderer - Indigo 0.4.3+6a2618f53a
fabric-renderer-registries-v1: Fabric Renderer Registries (v1) 2.2.0+6a2618f53a
fabric-rendering-data-attachment-v1: Fabric Rendering Data Attachment (v1) 0.1.4+6a2618f53a
fabric-rendering-fluids-v1: Fabric Rendering Fluids (v1) 0.1.12+6a2618f53a
fabric-rendering-v0: Fabric Rendering (v0) 1.1.1+6a2618f53a
fabric-rendering-v1: Fabric Rendering (v1) 1.5.0+c26373133a
fabric-resource-loader-v0: Fabric Resource Loader (v0) 0.4.1+0d4d7e343a
fabric-screen-handler-api-v1: Fabric Screen Handler API (v1) 1.1.0+6a2618f53a
fabric-structure-api-v1: Fabric Structure API (v1) 1.1.3+cbe9176f3a
fabric-tag-extensions-v0: Fabric Tag Extensions (v0) 1.1.0+e77439c73a
fabric-textures-v0: Fabric Textures (v0) 1.0.5+6a2618f53a
fabric-tool-attribute-api-v1: Fabric Tool Attribute API (v1) 1.2.5+6a2618f53a
fabricloader: Fabric Loader 0.11.0
java: Java HotSpot(TM) 64-Bit Server VM 8
litematica: Litematica 0.0.0-dev.20201103.184101
malilib: MaLiLib 0.10.0-dev.21+arne.2
minecraft: Minecraft 1.16.4
sodium: Sodium 0.1.0
wurst: Wurst Client v7.11-MC1.16.4
xaerominimap: Xaero's Minimap 21.2.0
Launched Version: fabric-loader-0.11.0-1.16.4
Backend library: LWJGL version 3.2.2 build 10
Backend API: GeForce GTX 1050 Ti/PCIe/SSE2 GL version 4.6.0 NVIDIA 456.71, NVIDIA Corporation
GL Caps: Using framebuffer using OpenGL 3.0
Using VBOs: Yes
Is Modded: Definitely; Client brand changed to 'fabric'
Type: Client (map_client.txt)
Graphics mode: fast
Resource Packs: vanilla, Fabric Mods
Current Language: English (US)
CPU: 4x Intel(R) Core(TM) i5-4440 CPU @ 3.10GHz

@LysergikProductions You are using an older version of Litematica. Try with the latest version.

If it still crashes, then try disabling the client fabric hiding feature whatever it was called in Wurst, that apparently causes this issue.