ive never seen anything like that. what we are trying to do is replicate it. so as much information as you can give the better.
game settings, or even a saved game file maybe helpful so we can try to narrow it down. if we can duplicate the problem, then the devs will have something to look into.
i personally havent seen it yet, but ive havent play that much entrenchment yet, and havent played advent. considering the number of people on this forum that were involved in the beta program, i would surprised if this is really a bug.