It seems to happen after I load from an instance, usually in NPC cities. It's happened to me three times now, two after exiting a successful siege (which isn't the best time for it to steal my food, wood, stone etc).
Or just interacting with a city, trade etc. I'll also note it doesn't seem to take my gold away, and leaves crowns also (I think).
The issue for me at least, seems to be there - as I'm finishing interacting with a city either from trade or siege. If there's specific information you need I can get you it the next time it happens, seems to happen to me fairly regularly so it shouldn't be an issue.
Last edited by Jacques : 01-26-2014 at 10:25 PM.