Hi there,
I recently played a game (poly bridge) witch static bars on the top and bottom for about 5 1/2 hours on my Lg V30 and after that I had some image retention of these bars. So far so good, on the next morning everything was fine again, but at the same evening after watching about 1 1/2 hours of video, I got not exactly the same effects, but a strange grey-ish stripe above only some of my multitasking apps and abovey volume slider (on the side) (I attached an image). Then on the next morning everything was fine again, and basically the same as the last day happened, but after I layed the phone down for about 10 minutes everything was fine again. And those bars also move, if I move the app in multitasking or the volume slider comes in and out. I feel like it recovers really fast, but no matter what I do, those effects come over time. I would be really glad if somebody knew the problem, even if it's to replace the screen (hopefully not).