I was starting to think I was the only one having this issue. Having the same problem on my 920. Hard reset didn't fix it. I rolled back to 8.1 - no issues in 8.1; then I re-updated to 10536 and the issue came back. It's frustrating that others are not having this issue on their 920's and I am. Unfortunately, I am back to 8.1 until a fix comes about. I didn't have the issue with 10512, but the performance wasn't so great, so I think I am sticking with 8.1 for now.
For me at least, this issue seems to only impact certain parts of the OS. My start screen is fine, as is my App list. Apps seem to be okay. But the Notification panel, dialer, keyboard and loading screens are all awful. Makes the phone unusable. Can't see most keys on the keyboard, even when entering a pin or password. So, there seems to be a graphics glitch in some core elements of the OS.
Edit: I saw a comment elsewhere that seems to more correctly identify the issue as a problem with overlay graphics.