It be nice if was random. I seem to consistently have this behavior with Codsworth and Jake with v1.0.4a. It would not be so bad except I can't get Jake to continue in the conversation, and it stops the quest. The part that makes me scratch my head is I've made it all the way through the first chapter of Jake using 1.0.2 and 1.0.3. using the same minimal mod list I have now. Well maybe I'll try flipping between them and see if I can find a culprit.Skyrim actually had the same issue with characters (mostly vendors) walking away from conversation and bumping into the wall behind them.
The Ron walks away every time he is at his desk and rams into the filing cabinets.