Going through my too-many mods to find a playable configuration, looks like there's some kind of conflict between Cases 0.3.2 beta, Repose 1.12-1.6.1, and Primitive Mobs 1.1.6 beta.

pastebin link

I'm not too worried about it, I'll just have to remember split them up over different profiles, but it might be something you want to look at for compatibility/bugs you didn't notice before. Or maybe it's an endemic incompatibility. Good luck and thanks for the mod either way!

(cross-posting to all three mods just in case)