Hello everyone.
I've been playing Half LIfe 2 - Episode two, and I'm really impressed by its graphics. I've noticed something weird though. In situations where smoke or mist should be, weird lines appear where the smoke intersects a surface:

I've marked the most evident lines with yellow arrows, but as you can see there are several thorughout the image.
Why does that happen? Is it how the game is supposed to be, or is it my hardware's fault?
I'm running the game on a GeForce 8800, and it would greatly disappoint me if it was because of the garphics card, since it's supposed to have been one of the best when the game came out...