I have had an issue 3 or 4 times where I shut down the 1040, it does the usual countdown on the solar screen, and then it stops on the screen with the power symbol:
It stays on that screen for as long as I have left it. Up to maybe 20 minutes. If I press and hold the power button for about 10 seconds it will go to the usual blank screen. Pressing power button again and it will power up normally. I haven't noticed anything in common when it does this (maybe 3 or 4 times out of 30 or 40 power downs. If I remember correctly, this has happened after finishing a workout and after it syncs. Otherwise, I don't know of any pattern and it is too infrequent to really watch.