It seems to be a multitude of affected tiles, ranging from parking lots, to bushes, to insides of buildings.
It has occured on every single GC i've played thusfar.
The strange thing, is that in the tile types affected, not all of the tiles are black. ie (30% are etc)
Here included is a screenshot.
http://steamcommunity.com/sharedfiles/filedetails/?id=227911579
Although, near the mid size scouts, the problem is worse.
http://steamcommunity.com/sharedfiles/filedetails/?id=227917619