I play on a 16:10 Monitor at 1920x1200 pixels and I’ve recently noticed things looking a little off, as if vertically stretched. Testing it, I’ve found that the game’s resolution actually changes to 1920x1080 when Alt-Tabbing out and back into the game.
Fortunately, exiting and re-entering fullscreen mode reverts the resolution change but it is rather annoying, having to do that every time.
I have attached two screenshots taken one after another. One after Alt-Tabbing out and back into the game and another after hitting Alt-Return twice afterwards.