Not certain if it's a load-order issue but the Dark Forests (minecraft:dark_forest biome) do not seem to generate with owls, moths, itching ivy, moth blossoms, foxglove, or black thistle when using Terralith. (Perhaps it's a terralith issue, I don't know).

MC: 1.19.2 fabric
Terralith_v2.3.5
architectury-6.2.46-fabric
biomemakeover-FABRIC-1.19.2-1.5.12
fabric-api-0.64.0+1.19.2.

This is happening for me too. It seems that Mushroom Fields content is also affected to a degree, with the mushroom caves nowhere to be seen.

So a bit more information...
I have seen

1. foxglove and black thistle in the dark forest, but not itching ivy, owls, moths
2. but there also appears to be an issue with generation of peat/mossy peat in swamps as well. but the "decayed" mobs are being generated.

I suppose I should learn a bit about modding Minecraft to see if I might be able to help (It's been a while since I coded java).

This comment is just an attempt to provide more context if that helps. (If it doesn't just ignore it).

Any update on that?

I'm not sure if the situation has changed since this report, but I've been able to locate all these features in a Terralith modified dark forest except moth blossoms and itching ivy.

I'm not really sure why, as the ivy/blossom patches are placed in the last generation step, while Terralith's trees are placed in the 2nd to last.

The /place feature biomemakeover:dark_forest/itching_ivy command also places them correctly.

I'm going to leave this issue open to collect more information if needed, but consider the two mods compatible as this is a minor issue.

Assuming these grow on the leaves of trees, I'm not seeing any naturally spawned moth blossoms or ivy in the minecraft:dark_forest biome either. Running /place feature biomemakeover:dark_forest/itching_ivy does indeed place them on leaves though. Moths are spawning just fine, however.

I'm running Biome Makeover 1.19.2-1.6.4 on Forge 43.2.8 in a modpack.