Thanks for your answer and suggestions.
I’ve tested it with both commands, the issue still persists.
It definitely only happens with the camera moving. I’ve tried it both with local lights included and not, no effect on the issue.
MegaLights are used, but have no effect on it, if turned off. I struggled with the very same issues back with UE5.3 already. Made a thread back then already as well, no one knew a working solution: Weird shadowy blobs around mesh
I found this official thread, which I believe is about that exact issue.
The suggested workarounds in there didn’t do much for me either though.
“Our study concluded that the most effective solution to this problem is to switch from Lumen to Ray Tracing GI lighting” - I wouldn’t even know if this is still possible to do in 5.5, global illumination method of “ray tracing GI lighting” isn’t listed as option in my project settings.
Here are two more displays:
I can literally watch the black areas disappearing in viewport, by going from one frame to another.