One of my 4k monitors has a bug, thankfully not noticeable most of the time. Tried to get it out or at least shift it loose so it can fall down to the bottom, but to no avail. So instead I just live with it, because it's close to the left edge and unless I fullscreen an app or the app over there has a bright background, I don't see it. It's annoying but not 'toss out an otherwise perfectly good monitor that I paid hundreds of dollars for and get a new one for hundreds of more dollars' annoying.