[MC-196534] Game does not recognize custom dimension type - "java.lang.IllegalStateException: Unregistered dimension type"

The game crashes upon creating a custom world with a dimension type defined as either an object, or as a string referencing a file under dimension_type/type.json, thus preventing custom dimension types from being used.

I've provided two versions of the file used to import the world settings, one defining the dimension type as an object, and the other referencing a file within the test datapack I've also attached.

(1.16.2 Pre-Release 1) crash-2020-07-30_00.23.26-server.txt

Description: Exception in server tick loop

java.lang.IllegalStateException: Unregistered dimension type: cgy@60fd51a1
	at net.minecraft.server.MinecraftServer.a(SourceFile:407)
	at net.minecraft.server.MinecraftServer$$Lambda$4243/2071520293.get(Unknown Source)
	at java.util.Optional.orElseThrow(Optional.java:290)
	at net.minecraft.server.MinecraftServer.a(SourceFile:407)
	at net.minecraft.server.MinecraftServer.l_(SourceFile:333)
	at emv.d(SourceFile:68)
	at net.minecraft.server.MinecraftServer.w(SourceFile:646)
	at net.minecraft.server.MinecraftServer.a(SourceFile:255)
	at net.minecraft.server.MinecraftServer$$Lambda$4065/2101823524.run(Unknown Source)
	at java.lang.Thread.run(Thread.java:745)