Which game did you see this in? By artifacts do you mean game texture corruption after using the overlay or something else?
In this case it is Shank 2. No corruption except for the overlay being present around the letter boxed view.
On Windows this kind of thing involves setting a flag on the game in the Steam backend info to clear on every frame to clean up the overlay rendering. This wasn't implemented on Linux and I added that, but this game is not marked for clearing. This will all get fixed up eventually.
@gdrewb-valve I suspected it was something like that. Thanks.
Closing as this appears to be fixed.
Nothing extracted yet.
While the latest client update might have fixed this for users of Intel hardware, it's still a issue with e.g AMD Catalyst 13.1 and Nvidia's 310.32. Any game occupying less screen real state should be affected by this.
My system information: https://gist.github.com/olavd/4377544, https://gist.github.com/olavd/4377514.