I believe this is really time dependent. It seems to occur if you wait about 2-3 seconds after pressing the power button before unlocking it again on the
iPad Mini running 6.0.2 and iPhone 5 running 6.0.1. I have not been able to get it to happen on normal iPads or devices running ios 5.x
When debugging it, the update and draw calls are still being made, but what is drawn seems frozen on the screen. It displays what was displaying on
the app before pressing the lock button. I was able to replicate this on TestCpp and HelloWorld after a few tries. It seems like it might happen more often
when there is more occurring in the draw code.