Lately I've been having this graphics bug. It's gray squares that seem to be everywhere, and when they're present they last from the beginning of deployment until the battle is over. They do not appear on the campaign map, and occur at approx. 20-30% of all battle maps, and more often during assaults than regular land battles.
I'm posting this here in DM forum because I'm using DM, and although it might not be related to this mod at all, I know some good people browse these forums.
Tons of +rep to anyone who would care to help. I'm sorry I can't provide any other information, as I really can't remember doing anything in particular that could cause this problem.
EDIT: Problem fixed. See my last post further down this page.
Here's a screenshot: