I gotta admit IDK in this case. I've seen something similar happen with a cold solder joint on the neckboard of a much older chassis. How regular is it? (The video is pretty bad, btw, so i can't really tell). If you run it in the dark, is anything sparking, or glowing that shouldn't be?
Wait a week or two on here, and if no one can answer, try posting up at this link because you never know -
https://www.aussiearcade.com/forum/62-monitor-and-chassis-repair-help/