I'm guessing this is a rolling shutter effect since the lines were always horizontal wrt the screen but can't really explain it. Shutter speed is 1/1500s. The lines appear on other shutter speeds too but fade away as you approach 1s. They seemed most noticeable at factors of 1/50s or 1/750s. Here's a screen video: https://quickshare.samsungcloud.com/xc6hikOCglkz