Hi @Dan C,
Thanks for your reply, I am attaching the video. (Just to prevent further confusion, I am using Ctrl+Z to revert every change I am making. In the end of the video, the Ctrl+Z actually caused the glitch as well.)
Note that this is happening in both Affinity Designer and Photo.
As you can see the canvas will sometimes refresh only when mouse is moving over it and never updates until then. I am not showing it on the video, but this can also happen when working with Layer Effects window or other interface. It even happens when changing some input using keyboard while mouse is on canvas, it only triggers the refresh when mouse starts moving.
I am not using any special software to mess with my GPU that could be causing it.
Let me know if you want to see my specs or GPU settings.
Thanks for looking into this, it drives me crazy!
Affinity refresh problem.mkv