This happened for the first time to me last night. I woke up around 0230, although I didn’t know it was 0230 at the time because my phone wouldn’t light up. When I took it off the charger, and put it back on the charger I heard the noise it makes when it makes connection to the charger so I knew the phone was still on. I restarted the phone and thank goodness I knew approximately where the slide to power off button was on the screen. When I turned the phone back on I saw the Apple logo and it lit up normally. I’ve only had the phone for a week, but I hope I never experienced this glitch again. Hopefully, Apple can come up with a solution to this issue. For reference, I use the charger that came in the box, and a Belkin quick charging cube.