My iPod Touch 4th generation (bought in November) screen commonly freezes for about 15-30 seconds. It usually happens when I am listening to music or a podcast and the iPod has been in sleep mode. By "freezes" I mean it is totally unresponsive. Touching the screen does nothing. Sometimes there will be artwork that is changing orientation, and it freezes halfway. It always eventually works, but these 15-30 second delays are somewhat annoying. Does anyone know of a solution to this issue?