Vibrant Visuals: Black pixels appear when look at spot with dim -> bright transition

When you look at a spot with a dim->bright transition (exit of a cave, for example) at certain angles, some black pixels appear and then slowly disappear. It seems to be a post process effect. I don’t know how to properly describe this, so I attached a video.

Video seed: 7580874593043645269, coords: -88 59 -10.