This still happened to me, man it was hard to find this post to fix it too, many rephrased google searches and whatnot. Both the Caesan in a small vent hiding in there preventing it from ending, and the wall popping out when damaged by a grenade. Wall that popped out was only the back right corner of the control room in the base though, if that matters.
Also while I'm at it a few more bugs. Had a troop walk onto railroad tracks in an industrial map, and get stuck there for the entire mission, unable to move but still able to turn and everything else. A few cases of aliens shooting through walls or completely blocked line of sight. Some research options available listed as #####.
