Yesterday I was building the roof of my small house using oak stairs. Everything was fine and when placing another one, it crashed. I'm not an expert but the crash report lets me guess that the error is caused by this mod. Using a different version of the mod didn't help. Uninstalling the mod and opening a copy of the world didn't work either.

The crash report I got when trying to open it with the latest 1.14.4 version of the mod:

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

Time: 19.02.20 19:43
Description: Tesselating block model

java.lang.NullPointerException: Tesselating block model
at snownee.kiwi.client.model.TextureModel.getQuads(TextureModel.java:269) ~[?:2.6.3] {re:classloading,pl:runtimedistcleaner:A}
at net.minecraft.client.renderer.BlockModelRenderer.renderModelSmooth(BlockModelRenderer.java:137) ~[?:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,xf:OptiFine:default,pl:mixin:A}
at net.minecraftforge.client.model.pipeline.ForgeBlockModelRenderer.renderModelSmooth(ForgeBlockModelRenderer.java:88) ~[?:?] {re:classloading}
at net.minecraft.client.renderer.BlockModelRenderer.renderModel(BlockModelRenderer.java:95) ~[?:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,xf:OptiFine:default,pl:mixin:A}
at net.minecraft.client.renderer.BlockRendererDispatcher.renderBlock(BlockRendererDispatcher.java:89) ~[?:?] {re:mixin,re:classloading,xf:OptiFine:default}
at mods.octarinecore.client.render.RenderCtx.render(BlockContext.kt:69) ~[?:2.5.0] {re:classloading}
at mods.octarinecore.client.render.CombinedContext.render(CombinedContext.kt:30) ~[?:2.5.0] {re:classloading}
at mods.octarinecore.client.render.CombinedContext.render$default(CombinedContext.kt:28) ~[?:2.5.0] {re:classloading}
at mods.betterfoliage.client.Hooks.renderWorldBlock(Hooks.kt:102) ~[?:2.5.0] {re:mixin,re:classloading}
at net.minecraft.client.renderer.chunk.ChunkRender.redirect$zzc000$renderBlock(ChunkRender.java:1015) ~[?:?] {re:mixin,re:classloading,xf:OptiFine:default,pl:mixin:A}
at net.minecraft.client.renderer.chunk.ChunkRender.func_178581_b(ChunkRender.java:385) ~[?:?] {re:mixin,re:classloading,xf:OptiFine:default,pl:mixin:A}
at net.minecraft.client.renderer.chunk.ChunkRenderWorker.func_178474_a(SourceFile:90) ~[?:?] {re:classloading}
at net.minecraft.client.renderer.chunk.ChunkRenderWorker.run(SourceFile:39) ~[?:?] {re:classloading}
at java.lang.Thread.run(Thread.java:745) ~[?:1.8.0_51] {}

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

-- Head --
Thread: Client thread
Stacktrace:
at snownee.kiwi.client.model.TextureModel.getQuads(TextureModel.java:269)
at net.minecraft.client.renderer.BlockModelRenderer.renderModelSmooth(BlockModelRenderer.java:137)
at net.minecraftforge.client.model.pipeline.ForgeBlockModelRenderer.renderModelSmooth(ForgeBlockModelRenderer.java:88)

-- Block model being tesselated --
Details:
Block: Block{snowrealmagic:stairs}[facing=east,half=bottom,shape=straight,waterlogged=false]
Block location: World: (-211,119,575), Chunk: (at 13,7,15 in -14,35; contains blocks -224,0,560 to -209,255,575), Region: (-1,1; contains chunks -32,32 to -1,63, blocks -512,0,512 to -1,255,1023)
Using AO: true
Stacktrace:
at net.minecraft.client.renderer.BlockModelRenderer.renderModel(BlockModelRenderer.java:95)

-- Block being tesselated --
Details:
Block: Block{snowrealmagic:stairs}[facing=east,half=bottom,shape=straight,waterlogged=false]
Block location: World: (-211,119,575), Chunk: (at 13,7,15 in -14,35; contains blocks -224,0,560 to -209,255,575), Region: (-1,1; contains chunks -32,32 to -1,63, blocks -512,0,512 to -1,255,1023)
Stacktrace:
at net.minecraft.client.renderer.BlockRendererDispatcher.renderBlock(BlockRendererDispatcher.java:89)
at mods.octarinecore.client.render.RenderCtx.render(BlockContext.kt:69)
at mods.octarinecore.client.render.CombinedContext.render(CombinedContext.kt:30)
at mods.octarinecore.client.render.CombinedContext.render$default(CombinedContext.kt:28)
at mods.betterfoliage.client.Hooks.renderWorldBlock(Hooks.kt:102)
at net.minecraft.client.renderer.chunk.ChunkRender.redirect$zzc000$renderBlock(ChunkRender.java:1015)

-- Affected level --
Details:
All players: 1 total; [ClientPlayerEntity['Timolino456'/205, l='MpServer', x=-211.23, y=119.00, z=575.10]]
Chunk stats: Client Chunk Cache: 1089, 729
Level dimension: DimensionType{minecraft:overworld}
Level name: MpServer
Level seed: 0
Level generator: ID 09 - ALPHA, ver 0. Features enabled: false
Level generator options: {}
Level spawn location: World: (228,66,-256), Chunk: (at 4,4,0 in 14,-16; contains blocks 224,0,-256 to 239,255,-241), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
Level time: 1307478 game time, 1538704 day time
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Server brand: forge
Server type: Integrated singleplayer server
Stacktrace:
at net.minecraft.client.world.ClientWorld.func_72914_a(ClientWorld.java:574)
at net.minecraft.client.Minecraft.func_71396_d(Minecraft.java:1750)
at net.minecraft.client.renderer.chunk.ChunkRenderWorker.run(SourceFile:45)
at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
Minecraft Version: 1.14.4
Minecraft Version ID: 1.14.4
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: 1727057712 bytes (1647 MB) / 4294967296 bytes (4096 MB) up to 4294967296 bytes (4096 MB)
CPUs: 12
JVM Flags: 8 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
ModLauncher: 4.1.0+62+5bfa59b
ModLauncher launch target: fmlclient
ModLauncher naming: srg
ModLauncher services:
/eventbus-1.0.0-service.jar eventbus PLUGINSERVICE
/forge-1.14.4-28.2.0.jar object_holder_definalize PLUGINSERVICE
/forge-1.14.4-28.2.0.jar runtime_enum_extender PLUGINSERVICE
/accesstransformers-1.0.1-milestone.0.1+94458e7-shadowed.jar accesstransformer PLUGINSERVICE
/forge-1.14.4-28.2.0.jar capability_inject_definalize PLUGINSERVICE
/forge-1.14.4-28.2.0.jar runtimedistcleaner PLUGINSERVICE
/OptiFine_1.14.4_HD_U_F5.jar OptiFine TRANSFORMATIONSERVICE
/forge-1.14.4-28.2.0.jar fml TRANSFORMATIONSERVICE
/MixinBootstrap-1.0.0.jar mixinbootstrap TRANSFORMATIONSERVICE
/MixinBootstrap-1.0.0.jar mixin PLUGINSERVICE
/MixinBootstrap-1.0.0.jar mixinbootstrap PLUGINSERVICE
FML: 28.2
Forge: net.minecraftforge:28.2.0
FML Language Providers:
[email protected]
minecraft@1
[email protected]
Mod List:
forge-1.14.4-28.2.0-client.jar Minecraft {[email protected] DONE}
SoundControl-1.14.4-0.0.5.0.jar §3Dynamic Surroundings
§eSound Control {[email protected] DONE}
Environs-1.14.4-0.0.5.0.jar §3Dynamic Surroundings
§eEnvirons {[email protected] DONE}
MouseTweaks-2.12-mc1.14.4.jar Mouse Tweaks {[email protected] DONE}
UndergroundBiomes-1.14.4-1.0-53.jar Underground Biomes {[email protected] DONE}
GoodSkeletonsDontStrafe-v1.1.2-1.14.4.jar Good Skeletons Don't Strafe {[email protected] DONE}
pamhc2crops-1.14.4-1.0.2.jar Pam's HarvestCraft 2 Crops {pamhc2crops@version DONE}
toughnessbar-4.1.jar Toughness Bar {[email protected] DONE}
betaplus-0.5f.jar Beta+ {[email protected] DONE}
jei-1.14.4-6.0.0.26.jar Just Enough Items {[email protected] DONE}
enchantable-1.1.0-mc1.14.4.jar Enchantable {[email protected] DONE}
AttributeFix-1.14.4-3.0.2.jar AttributeFix {[email protected] DONE}
MobEffects-1.14.4-0.0.5.0.jar §3Dynamic Surroundings
§eMob Effects {[email protected] DONE}
BowInfinityFix-1.14.4-rv7.1.jar Bow Infinity Fix {[email protected] DONE}
SpartanShields-1.14.4-2.0.0.jar Spartan Shields {[email protected] DONE}
Mantle-1.14.4-1.4.32.jar Mantle {[email protected] DONE}
AutoRegLib-1.4-35.jar AutoRegLib {[email protected] DONE}
FastWorkbench-1.14.4-2.1.4.jar FastWorkbench {[email protected] DONE}
Placebo-1.14.4-2.3.5.jar Placebo {[email protected] DONE}
SereneSeasons-1.14.4-2.0.0.14-universal.jar Serene Seasons {[email protected] DONE}
backpacked-1.2.0-mc1.14.4.jar Backpacked {[email protected] DONE}
randompatches-1.14.4-1.21.0.0.jar RandomPatches {[email protected] DONE}
FastFurnace-1.14.4-2.2.4.jar FastFurnace {[email protected] DONE}
AppleSkin-mc1.14.4-forge-1.0.12.jar AppleSkin {[email protected] DONE}
SnowRealMagic-1.14.4-1.5.2.jar Snow! Real Magic! {[email protected] DONE}
Kiwi-1.14.4-2.6.3.jar Kiwi {[email protected] DONE}
traverse-1.14.4-2.0.3.jar Traverse {[email protected] DONE}
FpsReducer-mc1.14.4-1.13.jar FPS Reducer {[email protected] DONE}
JustEnoughResources-1.14.4-0.10.0.70.jar Just Enough Resources {[email protected] DONE}
BetterThanMending-1.3.2.jar BetterThanMending {[email protected] DONE}
forge-1.14.4-28.2.0-universal.jar Forge {[email protected] DONE}
Quark-r2.0-210.jar Quark {[email protected] DONE}
Aquaculture-1.14.4-2.0.3.jar Aquaculture 2 {[email protected] DONE}
mysticallib-1.14.4-1.13.0.jar Mystical Lib {[email protected] DONE}
FastLeafDecay-v17.jar FastLeafDecay {fastleafdecay@v17 DONE}
overloadedarmorbar-3.0.0b.jar Overloaded Armor Bar {[email protected] DONE}
BetterFoliage-2.5.0-Forge-1.14.4.jar Better Foliage {[email protected] DONE}
BetterAdvancements-1.14.4-0.1.0.90.jar Better Advancements {[email protected] DONE}
Kiwi Modules:
kiwi:contributors
snowrealmagic:snowrealmagic
Launched Version: 1.14.4-forge-28.2.0
LWJGL: 3.2.2 build 10
OpenGL: NO CONTEXT
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: Yes
Is Modded: Definitely; Client brand changed to 'forge'
Type: Client (map_client.txt)
Resource Packs: mod_resources, vanilla, file/NewDefault+v1.25[MC1.13-1.14.4].zip, file/Toxs Vision [Beta v1.0].zip, file/Nate's+Tweaks+0.24+1.14.zip, file/Improved Chicken Model.zip, file/Kartixx's OAS Pack 1.14.4.zip, file/Shield+Corrections+§7[Regular].zip, file/Consistency-1.1.0.zip, file/Inconsistency-1.1.0.zip, mod:undergroundbiomesores
Current Language: English (US)
CPU: 12x AMD Ryzen 5 2600X Six-Core Processor 
OptiFine Version: OptiFine_1.14.4_HD_U_F5
OptiFine Build: 20191204-141250
Render Distance Chunks: 15
Mipmaps: 4
Anisotropic Filtering: 1
Antialiasing: 0
Multitexture: false
Shaders: Kappa_v2.0.zip
OpenGlVersion: 4.6.0 NVIDIA 441.87
OpenGlRenderer: GeForce RTX 2070 SUPER/PCIe/SSE2
OpenGlVendor: NVIDIA Corporation
CpuCount: 12

Duplicate of #52