Minecraft version: 1.16.4
Forge version: forge-1.16.4-35.1.37
Mod version: Quark-r2.4-308
Exception:
net.minecraft.crash.ReportedException: Feature placement at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:854) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:good_nights_sleep.mixins.json:MinecraftServerMixin,pl:mixin:APP:betterendforge.mixins.json:MinecraftServerMixin,pl:mixin:APP:charm.mixins.json:accessor.MinecraftServerAccessor,pl:mixin:A,pl:runtimedistcleaner:A} at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:291) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:786) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:good_nights_sleep.mixins.json:MinecraftServerMixin,pl:mixin:APP:betterendforge.mixins.json:MinecraftServerMixin,pl:mixin:APP:charm.mixins.json:accessor.MinecraftServerAccessor,pl:mixin:A,pl:runtimedistcleaner:A} at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:641) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:good_nights_sleep.mixins.json:MinecraftServerMixin,pl:mixin:APP:betterendforge.mixins.json:MinecraftServerMixin,pl:mixin:APP:charm.mixins.json:accessor.MinecraftServerAccessor,pl:mixin:A,pl:runtimedistcleaner:A} at net.minecraft.server.MinecraftServer.lambda$startServer$0(MinecraftServer.java:232) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:good_nights_sleep.mixins.json:MinecraftServerMixin,pl:mixin:APP:betterendforge.mixins.json:MinecraftServerMixin,pl:mixin:APP:charm.mixins.json:accessor.MinecraftServerAccessor,pl:mixin:A,pl:runtimedistcleaner:A} at java.lang.Thread.run(Thread.java:830) [?:?] {} Caused by: java.lang.NullPointerException at vazkii.quark.base.world.config.StrictBiomeConfig.canSpawn(StrictBiomeConfig.java:30) ~[quark:r2.4-308] {re:classloading} at vazkii.quark.base.world.config.IBiomeConfig.canSpawn(IBiomeConfig.java:10) ~[quark:r2.4-308] {re:classloading} at vazkii.quark.content.world.gen.BigStoneClusterGenerator.isSourceValid(BigStoneClusterGenerator.java:29) ~[quark:r2.4-308] {re:classloading} at vazkii.quark.base.world.generator.multichunk.MultiChunkFeatureGenerator.generateChunk(MultiChunkFeatureGenerator.java:50) ~[quark:r2.4-308] {re:classloading} at vazkii.quark.base.world.generator.Generator.generate(Generator.java:35) ~[quark:r2.4-308] {re:classloading} at vazkii.quark.base.world.WorldGenHandler.generateChunk(WorldGenHandler.java:208) ~[quark:r2.4-308] {re:classloading} at vazkii.quark.base.world.DeferedFeature.func_241855_a(DeferedFeature.java:24) ~[quark:r2.4-308] {re:classloading} at vazkii.quark.base.world.DeferedFeature.func_241855_a(DeferedFeature.java:13) ~[quark:r2.4-308] {re:classloading} at net.minecraft.world.gen.feature.ConfiguredFeature.func_242765_a(SourceFile:55) ~[?:?] {re:classloading} at net.minecraft.world.gen.feature.DecoratedFeature.func_242772_a(SourceFile:23) ~[?:?] {re:classloading} at java.util.Iterator.forEachRemaining(Iterator.java:133) ~[?:?] {} at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801) ~[?:?] {} at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:658) ~[?:?] {} at net.minecraft.world.gen.feature.DecoratedFeature.func_241855_a(SourceFile:22) ~[?:?] {re:classloading} at net.minecraft.world.gen.feature.DecoratedFeature.func_241855_a(SourceFile:14) ~[?:?] {re:classloading} at net.minecraft.world.gen.feature.ConfiguredFeature.func_242765_a(SourceFile:55) ~[?:?] {re:classloading} at net.minecraft.world.biome.Biome.func_242427_a(Biome.java:254) ~[?:?] {re:classloading,pl:accesstransformer:B,xf:fml:sereneseasons:temperature_transformer,pl:runtimedistcleaner:A,re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A} at net.minecraft.world.gen.ChunkGenerator.func_230351_a_(SourceFile:220) ~[?:?] {re:mixin,re:classloading} at net.minecraft.world.chunk.ChunkStatus.lambda$static$9(ChunkStatus.java:77) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.world.chunk.ChunkStatus.func_223198_a(ChunkStatus.java:198) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.world.server.ChunkManager.lambda$null$18(ChunkManager.java:524) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:A,pl:runtimedistcleaner:A} at com.mojang.datafixers.util.Either$Left.map(Either.java:38) ~[?:?] {re:classloading} at net.minecraft.world.server.ChunkManager.lambda$chunkGenerate$20(ChunkManager.java:522) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:A,pl:runtimedistcleaner:A} at java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:1146) ~[?:?] {} at java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:478) ~[?:?] {} at net.minecraft.world.chunk.ChunkTaskPriorityQueueSorter.func_219083_b(SourceFile:58) ~[?:?] {re:classloading} at net.minecraft.util.concurrent.DelegatedTaskExecutor.func_213148_e(SourceFile:94) ~[?:?] {re:classloading} at net.minecraft.util.concurrent.DelegatedTaskExecutor.func_213145_a(SourceFile:137) ~[?:?] {re:classloading} at net.minecraft.util.concurrent.DelegatedTaskExecutor.run(SourceFile:105) ~[?:?] {re:classloading} at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1425) ~[?:?] {} at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290) ~[?:?] {} at java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1016) ~[?:?] {} at java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1665) ~[?:?] {re:computing_frames} at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1598) ~[?:?] {re:computing_frames} at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:177) ~[?:?] {} Exception in thread "WorldCacheIOThread"

Probably easiest to add a null check here