Using the end type with end terrain generation in other dimensions creates the dragon fight as if it was in the end, similar to spawning an ender dragon with commands except the fight works, however killing the dragon crashes the game immediately causing the world to roll back. Attempting to enter the end portal also crashes the game upon entering inside which could be related or tied in some way to
MC-184948 which does not crash the game and has a much different response when entering.
It seems to matter if the end type is used. Using other types does not crash the game especially overworld.
Description: Colliding entity with block
java.lang.NullPointerException: Colliding entity with block
at yw$$Lambda$3985/93031781.accept(Unknown Source)