If you're wondering what issue I'm talking about, here's a youtube video of it happening: Youtube.com
It's come to my attention that a few people have had some issues with the large amount of vegetation I've plastered on my level. The issue is sometimes the game will freeze up and go all bright if you look in certain directions. I believe this only happens on Very High graphic settings, but with a simple command punched into your console, all should be fixed.
1: Open the console with the tilde key (to the left of the 1 key).
2: Type "e_view_dist_ratio_vegetation=45", press enter to apply the change.
3: If this doesn't stop the issues, try a lower value such as 40 or 35.
Hopefully that clears up the problem, I've never had it, so I can't say, but if it works for you (or doesn't), please comment below telling me the results.