Is anyone else having issues where they will pick up their iPhone and it simply does not respond at all? It runs fine but several times a day I will pick it up and no button presses will wake it up or get it to respond. I have to restart it each time which gets annoying. Can't seem to isolate it, I did a restore as new and didn't install any apps and it still did it. This started pretty much the day of 3.1 release.