After updating my server from 1.17 to 1.18 I entered new chunks and a witch hut generated in a warm ocean biome ~64 blocks away from the swamp. After looking around in spectator, part of the swamp is 1.17 terrain with the last couple blocks before the ocean being 1.18. Indicating this hut placement is probably caused by the seamless world generation.

Expected Behavior:

Witch hut generated only in swamps

Observed  Behavior:

Witch hut generated outside of swamp.

(Even though I am running fabric I have no mods installed)