I would check/swap your HDMI cable to be sure it's maintaining a solid connection. Had erratic problems like this with my 4k BlueRay player using the same cable as a previous BluRay that had no issues. Finally decided to begin swapping cables and it wasn't until the 3rd cable things stayed solidly locked, receiver kept swapping inputs like it had been flipped off, video feed would cut out, just erratic stuff like that, SQ/VQ changes would make sense if it doesn't detect the cable can support the highest settings it falls back possibly. (I need to buy a higher quality one for that in the near future, but found one that has been solid out of my existing set at least). Something to check anyhow.