How to reproduce:

1. Load up a nether or end biome as a single biome world

It seems like only the basalt columns and structures generate correctly. Mobs spawning, sky color, and particles also works.

Observed Result (using seed 301546615553008431):
Crimson Forest

Warped Forest

Basalt Deltas

End Highlands

Expected Result (using seed 301546615553008431 in 1.17.1):
Crimson Forest

Warped Forest

Basalt Deltas

End Highlands