This appears to be graphic corruption. Let's do this test:
1. Go to Photoshop>Preferences>Performance.
2. Uncheck "Enable OpenGL Drawing", click OK.
3. Reopen the image.
If the behavior goes away, it is time to uninstall and reinstall the video driver for your video card.
Worked like a charm. Not sure how you knew that but thanks a lot!
Random pixels like that usually mean a bad GPU or bad VRAM on the video card.
You're likely to see them in any application that uses the GPU.
And the only good solution is to replace the video card.