Just played the map on standard difficulty and had the same issue. What i think is interesting is that although the match has crashed and i could not control anything in that moment, a few AI units still attacked my units and my units fought back. Will see if i can reproduce that one and get a clip out of it.
EDIT: Could reproduce the case. After the 3rd wagon has done half the way (see Picture 3+4) units become uncontrollable, cards won't work. Both times the game continues a little bit after control is lost, AI units and my units fight and after the enemy units die the game freezes aft