Hi, I've found yet another possible cause and (hooray!) fix. Try fully dismissing any followers (and/or finishing quests that provide a temporary NPC follower). Don't just tell them to wait - send all companions home. I think what was happening, in my game at least, was that I was being pushed off grindstones etc by the AI running the follower animation to use whatever upgrading object I wanted to use. This is even if you tell them to stand far away or in another area. To be absolutly certain, I went back to a save before the bug started happening, dismissed all followers and then grabbed back the ones I wanted. The bug, so far, hasn't come back. A bit of a pain, but better than bug hunting through a couple of hundred mods. Hope this helps.