Sorry but this is not a Beta 3 bug. I tried IOS 7 on my iPhone 4. Beta 1 was fine, beta 2 resulting in my phone basically turning off and not responding twice within a week. I could be using it one minute, lay it down and when go to use it again it would not respond, the screen would remain black. After a few hours it did turn back on with me consistently trying the power button (i was at work and it happened at about 11am, by about 5:30pm the phone started working again). This never happened in IOS 6 and has not happened since i reverted back to IOS 6. Sadly other then the occasional app not working I liked IOS 7.