Oh, i have exactly the same problem..
My graphic card is geforce 4, weak card.
I think this prob appears in weak cards that dont support some thing that cause this thing...
Maby soon some one will release a patch or something that will fix this prob, hopefully :[
But still there is something strange, becuz if you look down, usually you see the game like it need to be, but when you look upper, this prob appears again.
Also when you start the game, you can return back and you will see the map as it need to be.
Very strange..
