I think I have a similar issue to this too. I do get those screen lines on low brightness. What happens to mine though is that sometimes when I double tap, I can not wake up the display from the stand-by/glance screen. Even with the stand-by/glance option disabled in settings, I would still come upon that same issue except I would only get the black screen (display is still active though). I can kind of feel my way around the homescreen and stuff, but the display is still black. My only quick solution is to hold the power and up keys to powercycle it, then it gets back to normal. I'm assuming the display is getting weak? I mean it has been dropped quite a few times.