Game crashes (ArrayIndexOutOfBoundsException) during world feature placement / decoration

The bug

The game crashes with java.lang.ArrayIndexOutOfBoundsException during world feature placement / decoration. I am unsure of the cause of this issue. It was showcased in this video by Phoenix SC, and I could reproduce.

A crash report is attached.

How to reproduce

1. Select Singleplayer -> Create New World -> More World Options...

2. Change World Type to Superflat, and select Customize -> Presets

3. Select Tunnelers' Dream

4. Change the preset code to

   100*minecraft:stone

5. Select Use Preset -> Done -> Create New World
   ❌ Crash

If the game does not crash, you may need to try it a few more times.

Stack trace

21w08b\: [^crash-2021-03-04_08.47.11-server.txt]

Description: Feature placement

java.lang.ArrayIndexOutOfBoundsException: -1
	at ckf.b(SourceFile:62)
	at cke.a(SourceFile:30)
	at it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap.computeIfAbsent(Long2ObjectOpenHashMap.java:479)
	at cke.a(SourceFile:28)
	at cke.b(SourceFile:40)
	at cpq.a(SourceFile:165)
	at cpq.a(SourceFile:173)
	at cqr.a(SourceFile:180)
	at cqr.a(SourceFile:155)
	at cqr.a(SourceFile:53)
	at coy.a(SourceFile:55)
	at cpe.a(SourceFile:29)
	at java.util.stream.Streams$StreamBuilderImpl.forEachRemaining(Streams.java:419)
	at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:580)
	at cpe.a(SourceFile:28)
	at coy.a(SourceFile:55)
	at cpe.a(SourceFile:29)
	at java.util.stream.Streams$StreamBuilderImpl.forEachRemaining(Streams.java:419)
	at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:580)
	at cpe.a(SourceFile:28)
	at coy.a(SourceFile:55)
	at cpe.a(SourceFile:29)
	at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
	at java.util.stream.IntPipeline$4$1.accept(IntPipeline.java:250)
	at java.util.stream.Streams$RangeIntSpliterator.forEachRemaining(Streams.java:110)
	at java.util.Spliterator$OfInt.forEachRemaining(Spliterator.java:693)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
	at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
	at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
	at cpe.a(SourceFile:28)
	at coy.a(SourceFile:55)
	at bvn.a(SourceFile:380)
	at ckh.a(SourceFile:233)
	at ckj.c(SourceFile:100)
	at ckj.a(SourceFile:231)
	at aau.a(SourceFile:563)
	at com.mojang.datafixers.util.Either$Left.map(Either.java:38)
	at aau.a(SourceFile:557)
	at java.util.concurrent.CompletableFuture.uniCompose(CompletableFuture.java:952)
	at java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:926)
	at java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:442)
	at aaw.b(SourceFile:58)
	at apt.e(SourceFile:84)
	at apt.a(SourceFile:124)
	at apt.run(SourceFile:92)
	at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1402)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)