That is DFAO and it can look pretty rough like that, it’s the dynamic lighting system other than Lumen and SSGI.
You can control DFAO in the skylight. As far as I’m aware, there is no way to make the output smoother like something you would see in this clip (the ao that disappears) which you would think would be target output for DFAO at this point. But we splotch instead or over blown memory usage.