Yeah tried that & problem still there. I even did a clean install with the new video driver after the original post with no change. Funny thing is when I first start the game the sky is perfect but after about 5 mins the big white areas appear. Also after the original post I went a couple of streets away, brought the phone up on the screen & went away from the pc for about an hour to do something - when I came back the sky was perfect but then after a few mins of playing the glitch appeared again. Did another search & couldn't find anyone discussing this particular issue so can't be a common one. Annoying!
Here's a shot I just took with settings at Low. Daytime now so it's even clearer -
