Switching the graphics quality from Low, Normal or Extreme to any other setting while playing causes a blank screen with no audio. The game doesn't appear to be locked up, but there's no response to any input. I can tab out easily and close the window and restart the game.
This is consistently reproducible on my end. It does this in both windowed and fullscreen mode. Switching graphics quality from the menu before starting a game still works fine.
Here's a very uninteresting screenshot of what it looks like in windowed mode. Very blank as you can see
