Not taking credit for this, found it after some googling.
Original thread here: http://www.bulletstormforum.com/bull...ing-bug-2.html
If you've been seeing a diagonal line across your screen whenever your view is near the sun, the problem is related to your Graphics card. A lot of people with ati 6970s and 6950s have been seeing this kind of thing.
It's a post processing error. To fix:
Unencrypt your StormEngine.ini
Search for lightshaft
Set it to false.
Reincrypt the ini.
Obviously it's an engine bug that needs to be fixed so hopefully epic will patch this.