I think it's an ios8 problem. I had it on my iPhone 5 on ios8 and the screen was jumping around. Had to live with it for nearly a year. Just recently updated iPad Air from iOS 7 to 8 and now the iPad is jumping around too, first when it was on charge. Didn't do that at all on ios7. Can't remember if my iPhone 5 did that when not on charge or shortly after one. It's very annoying though,