And I had a battle where an AI-catapult "hopped" on one of my heroes when he neared it. I could find his real place (it was invisible there) and attack it when scanning for his probable location with the mouse and waiting for a for a change of the cursor. Perhaps the withdraw a tile animation is bugged?
Another catapult bug: I entered a fortress with a lone (produced) catapult in it with a stack of 8 heroes. Next turn the catapult was gone forever (I wasn't training something in the fortress).