This sounds very similar to the issue that I have and posted about a while ago:
In my case, as mentioned, it appears that the flickering (and resultant semi-permanent screen 'damage') is caused by dithering. I found that this was due to the default dithering settings, which, for me, are
- Current Dithering: Enabled
- Current Mode: Dynamic 2x2
- Current Depth: 6bpc
Changing any of these, i.e.
- Enabled -> Disabled, or
- Dynamic -> Static, or
- 6bpc -> 8bpc
stops the flickering. I just disable dithering.
Is this the same for others here?