Forge version: 36.1.0
Twilight Forest version: 4.0.433

Steps to reproduce:

1. Spawn a mob with a changed model, ie. Wild Boar, Deer, Questing Ram

What happened:

As the new textures have different UVs, whether parts have been shuffled around or a completely new texture map was created, the textures for the old models are no longer compatible. See below examples of the classic pack in effect on the new models.

Issue moved to 1.18 Milestone for potential 1.18 model json deserialization