I haven’t seen this in more than a year and it was a little different.
I’m on 4.9.2, and the right eye has a checkerboard grid with and without shadows. Oculus 0.7 358.70+358.78 and 0.8 358.78 on a 980 ti on windows 10 64-bit. I clean-reinstalled everything but the OS. I should probably mention that I also had installed a Radeon 7990 which shows no such issues.
Did anyone see anything similar recently? I was thinking a display issue because I see the shadows are rendered just not displayed correctly, almost as if they are following a z-depth buffer with insufficient precision and thus parts of the shadows are overlayed and parts are drawn before the final image.
Edit: It only happens with raytraced distancefield shadows so it must be a bug. Will try to rollback drivers as I distinctly remember this was working fine in VR.