I've had a lot of trouble getting Lydia to follow me through doorways in dungeons. She often just stops as I'm running through and I have to backtrack to coax her through, after loading the game because I rushed into a battle without backup. Most recently, I've noticed that she won't follow me into the buildings just outside Mzinchaleft (the spot opposite the entrance to the ruins, where you arrive if you quick travel there).

It's annoying. I can see not having A.I. jump at all.. maybe... even that is sort of lame, but not being able to cross a threshold that I simply walk over?

It's a minor bug, but it comes up a lot the way I play. She'll run around a big hill even though I'm not jumping to get where I am.