there but not really

while playing CONSTRUCTION co-op mission with a buddy he appeared on a rock next to me but he was actually across the map. I could see in real time what he was doing as long as he was on the rock. even mini map showed him next to me. when he left the rock he was magicly back at his location on mini map and invisible to my player. I could see him but he didn't know anything was going on. other than being very odd, game play did not appear to be affected for either of us. this was also at the tail end of a storm.