Sometimes leaving the battlefields and then returning fixes the problem....
Otherwise you may have a corrup dynamic file....
Try deleting the files in the dynamic folders;
'..\Beyond Divinity\Acts\Act1\Dynamic', '..\Beyond Divinity\Acts\Act2\Dynamic', etc.
These folders are used as a cache for the game. Files are created / copied there from the save game folder when you load, and written / copied to those folders when you save a game. The files will be re-created as required the next time you start Beyond Divinity. If there was a corrupt file in those folders, deleting the files should fix the problem.
what you can also try is double clicking the portrait of your character, this fixes the black maps in a couple of cases, or pressing "a" and then exiting the map again...
