Sorry to hear you're experiencing troubles. I don't think I've had this sort of problem reported before. Would you mind emailing me a copy of your game log from a play session where this has happened to the address listed under the "Technical help" section here on the store page?
Edit: Just to follow up in case anybody else is experiencing graphical glitches with Intel graphics chipsets on Windows, driver 26.20.100.7262 was causing issues that were resolved by 27.20.100.9168.