Just checked a few things and it’s definitely HDR related. Play an HDR video on Youtube and double tap left or right in the video to skip x seconds back or ahead and you see this circular animation overlay on the video. this also shows the weird reddish broken up stepping effect. Go to a regular video and do the same and the artifact is not there. Has anyone tried playing HDR with VLC? I’ll see if I can do some comparisons tomorrow.
Edit: My display is otherwise perfect. No green tint in grey areas, also not on very low brightness setting.