Parts of screen darken as the camera turns

Any ideas why parts of my scene darken dramatically when the camera turns?
It’s as though there’s a screen of dark pixels being rendered over the scene.
(I’m using UE4.27.1 on Windows 10)


Are you using contact shadows?

Arkiras - yes, we are using contact shadows…
The screen darkening issue went away after a restart. The next time I see it I’ll try changing the contact shadow settings.