I have had intermittent issues like this as well, but usually just closing and relaunching the game fixed them immediately. It's obviously graphic related, but I can't really say if it's your graphics driver, or just a file didn't load correctly on launch.
The best example of this is when someone posted a screenshot of the face skins replacing a lot of the ground textures, and some giant mountain had a stretched out face texture. That was hilarious.
