I've experienced this occassionally from the time I purchased this unit.
Sometimes when I power off, the unit does not do a normal shutdown. This happened again yesterday. I have no power light, normally it would be red. Most likely when I power on it won't be a normal start up, a may have to reboot the unit.
It doesn't seem to matter where I am when I power off. I've been coming back to the home screen and situation was stable until yesterday.