Sometimes, on slopes, I'll be messing around and die, and it'll be like I'm holding a gigantic light; the ground gets extremely bright when I go near it. Sometimes it'll do the same thing, but "melt".... It'll turn brown, but only as I go near.
Ya it was doing that too when I shot a rocket, the whole ground lit up
Look in base/data/terrains. If there is a "default.JPG" file, delete it and restart the game. That fixed it for me, although it didn't exist for some other people.
Doing this will cause you to have purple terrain at some point in the future. The correct answer is to re-install the game and this time don't edit the map like a moron.
It seems to be linked to the combat jeep or whatever.