I bought a fourth generation iPad in November. I started noticing this problem a couple weeks after receiving it. It seems to occur when watching videos from iTunes on the native video app, on the Amazon Instant Video app and on HBO Go. I have not noticed much of a problem when using Netflix, which is very odd. I also notice that the color of the playback controls start to fade in color when you tap the screen during playback. The blue become a very light blue, like it is washed out. And if you do a pinch to close the player during playback then the home screen has that same washed out look for a couple seconds. This is VERY ANNOYING. I have purchased the iPad 2, the iPad 3 and now the iPad 4 and all have had some sort of issue. I had the 2nd and 3rd generations replaced and now I'm considering trying to get this one replaced as well.