I've been getting a weird graphical bug, when I'm heading south it will randomly pick a row of tiles on the bottom of the map screen, and just keep displaying them over the bottom row of the map as I move around. It covers up whatever I'm supposed to see, and will occasionally go aways when I head north. Although, even if I get it to it to go away, it comes back again if I head south again. Is there any way to fix this?