Backlight bleed
Also called light bleed · clouding
Backlight bleed is light leaking around the edges of an LCD panel. It shows as bright patches near the corners on a black screen in a dark room.
Bleed stays in the same place when you move your head. That separates it from IPS glow, which shifts with viewing angle.
In practice
Bleed is mostly visible in dark scenes in a dark room: film letterboxing, game loading screens and night scenes. A little at the edges is normal on almost every LCD. It becomes a problem when you can see it in normal use or when it spreads well into the picture. It doesn’t move with your head, which separates it from IPS glow.
How to check
Show full screen black in the dead pixel test, dim the room and look from your normal seat. Then move your head side to side. Bright patches that stay put are bleed. Judge by eye rather than a phone photo, since cameras exaggerate it. Raise it with the retailer while you are inside the return window.