A handful of OnePlus 6T users are complaining about an odd issue with the display. There are some reports on the official OnePlus forums where 6T owners are experiencing a weird behaviour that is easier to demonstrate than describe. Check out the video below to see what happens. In a nutshell, a static wave travels up or down on the screen. It looks like some pixels are lighting up.
Apparently there’s no way to replicate this, and, while it happens in the notification shade in the example below, some users reported seeing this behaviour on the lock screen as well. Apparently, it’s not specific to a particular model, and a factory reset doesn’t fix the issue. Thankfully, those who are experiencing this are reporting that it only happens occasionally, so it’s not an annoying thing, but still a problem.