How do I solve a problem with The Sims 3 characters resetting their animation during certain interactions?

Recently, while I was playing The Sims 3 in the university setting, I attempted to greet someone and something weird happened. My sim approached them, started to talk, then suddenly jumped 10 feet back to where they started with the interaction not happening. After some experimentation, I've found that it happens on most of the greetings (oddly enough the Charming Greeting works for those sims charismatic enough to do it), some of the romance options, and any form of socialization at work or in class (they actually warp outside the building as if they decided to leave when it cancels). I have tried the resetsim console command. I've tried deleting the cache files. I've tried backing up the directory in My Documents, starting afresh, and restoring files one by one, but I haven't found a solution yet.

Poking around online, it seems like I'm far from the first person to encounter this, and I've been trying proposed solutions, but no one seems to have actually found one. Could it be because these characters didn't start off with the University expansion? I only had the base game and a few expansions, picked up from Origin during a bundle sale, but recently happened upon a copy of University Life in our local thrift shop and was thrilled because I enjoyed university in The Sims 2.