java.lang.IllegalArgumentException: bound must be positive

I'm trying to generate a custom floating islands nether dimension with extended min y/height using a datapack. When I go into the nether, the game crashes. Both the crash report and the datapack are attached.

I would also like to state that it only happened once - it appears that subsequent attempts on the same world makes it crash (I don't have the world anymore) and subsequent attempts on different worlds makes the game hang.

21w19a: [^crash-2021-05-17_12.28.17-server-1.txt]

ava.lang.IllegalArgumentException: bound must be positive
	at java.base/java.util.Random.nextInt(Random.java:388)
	at dah$a.a(SourceFile:42)
	at dah$a.a(SourceFile:30)
	at ctk.a(SourceFile:268)
	at cqw.a(SourceFile:36)
	at clv.a(SourceFile:309)
	at clv.a(SourceFile:292)
	at clx.e(SourceFile:53)
	at clx.a(SourceFile:231)
	at aay.a(SourceFile:563)
	at com.mojang.datafixers.util.Either$Left.map(Either.java:38)
	at aay.a(SourceFile:557)
	at java.base/java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:1146)
	at java.base/java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:478)
	at aba.b(SourceFile:58)
	at aqh.f(SourceFile:92)
	at aqh.a(SourceFile:132)
	at aqh.run(SourceFile:100)
	at java.base/java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1434)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:295)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1016)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1665)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1598)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:183)


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

-- Head --
Thread: Server thread
Stacktrace:
	at java.base/java.util.Random.nextInt(Random.java:388)
	at dah$a.a(SourceFile:42)
	at dah$a.a(SourceFile:30)
	at ctk.a(SourceFile:268)
	at cqw.a(SourceFile:36)
	at clv.a(SourceFile:309)
	at clv.a(SourceFile:292)
	at clx.e(SourceFile:53)
	at clx.a(SourceFile:231)

-- Chunk to be generated --
Details:
	Location: -6,0
	Position hash: 4294967290
	Generator: cpb@1c158b9
Stacktrace:
	at aay.a(SourceFile:563)
	at com.mojang.datafixers.util.Either$Left.map(Either.java:38)
	at aay.a(SourceFile:557)
	at java.base/java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:1146)
	at java.base/java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:478)

-- Player being ticked --
Details:
	Entity Type: minecraft:player (abm)
	Entity ID: 1
	Entity Name: VirxEC
	Entity's Exact location: 169.14, 201.87, -249.70
	Entity's Block location: World: (169,201,-250), Section: (at 9,9,6 in 10,12,-16; chunk contains blocks 160,-64,-256 to 175,319,-241), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,-64,-512 to 511,319,-1)
	Entity's Momentum: 0.00, 0.00, 0.00
	Entity's Passengers: []
	Entity's Vehicle: null
Stacktrace:
	at abm.l(SourceFile:529)
	at acd.b(SourceFile:213)
	at nz.a(SourceFile:238)
	at acc.c(SourceFile:183)
	at net.minecraft.server.MinecraftServer.b(SourceFile:887)
	at net.minecraft.server.MinecraftServer.a(SourceFile:816)
	at ezw.a(SourceFile:96)
	at net.minecraft.server.MinecraftServer.x(SourceFile:674)
	at net.minecraft.server.MinecraftServer.a(SourceFile:261)
	at java.base/java.lang.Thread.run(Thread.java:831)