Bad Viewport Quality - only while Playing Level

When I start simulating as the ‘player controller’, the vewport becomes very blurry with artifacting and twitching. If I eject from the player controller or stop simulating the viewport is normal. I tried making a new, blank project and it does the same thing.

If I stay still long enough, the picture starts to clean up.

How do I stop this and go back to default behavior?

simulated, with player controller

normal, ejected