Has happened to me more than once – you accept a job escorting a caravan, then you are attacked and win, but after that the caravan doesn’t start moving again.
The rest of the game appears to go on, if there are other enemies nearby they attack the frozen caravan.
It is not so bad because you can avoid the bug if you save after the fight, and reload that save. The caravan then goes back to moving as usual.
It is a bit annoying and immersion-breaking.
I will edit with the dxdiag, log and such, but tomorrow. Kind of late here, just wanted to let you know before i had forgotten it.