I had the same problem as well, but with my player character, including the part where she seems to be "stuck" in time (I command her to move, then when her turn comes around again, she's back in the original position). I ended up having Astarion shoot her from afar to kill her and then paying Skelly to res her and the problem was resolved, but I thought I should bring this up nonetheless in case Larian wasn't yet aware. I captured the bug in this video:
https://youtu.be/-WyM2oTK2p0 You can see that PC can move but warps back to the starting location, and also can't do any of the actions/bonus actions - the animation for the spells seems to be off as well. At this time I had just killed a pack of hook horrors down there and I had the myconid sovereign Glut with me. I can't recall anything else of note before that.
