Updated to 1.9.15, got rid of incompatible mods. I know fisobs has yet to update, but this happened even on vanilla regions/creatures.
The game will just freeze. Itll only freeze creatures/entities, while environment animations still play. For some reason, the only way this is remedied is by holding B with dev tools on. I thought it was an issue with beastmaster, but removing that didnt fix it either. Simply pressing B doesnt work too well as it freezes up as soon as you let go of it.
One can see how this might make for some problematic gameplay 