Forge version: 1.16.5 - 36.1.24
Twilight Forest version: 1.16.5 - 4.0.490

Steps to reproduce:

1. enter the dimension and check them out

What I expected to happen:
Things work normally i guess
What happened instead:

1. Naga only has a head
2. Hydra missing all heads
3. Snow Queen missing the ice cloud
4. Hollow hills have nothing inside
5. firefly_forest biome is empty
   
   
   
   

first 3 problems derive from optifine, rest seems to be a bug, do you have other mods other than optifine?

first 3 problems derive from optifine, rest seems to be a bug, do you have other mods other than optifine?

DiagonalFences DoggyTalents gravestone Hwyla JEI mcw-bridges mcw-fences Patchouli StorageDrawers tablechair
that's all

1, 2, and 3 all sound like issues with Optifine. This is something we cannot fix except for a warning on the start screen stating that bugs like this will happen and only they can fix.

4 is definitely a bug, though it appears to be random when this happens.

5 is what happens when a mod that adds additional block states - such as Diagonal Fences - is added to a pack. Unfortunately, those mods are adding block states "dangerously" and can break datapacks, which is where worldgen is handled, too. We cannot do anything about this, either.

I would like to note that separate tickets should be opened for each bug. It's much easier to track; this issue has 4 unresolvable issues and 1 confirmed issue, however it would be confusing to keep this open as it implies he other 4 are related, which the are not in this instance.