Originally Posted by yossiw
what is your charging device?, try to charge with the original charger
(no usb or any other charger)
I can tell you from my own experience that it's definitely a problem with the charger. The Samsung charger works, and I have a few others that work, but most will prevent the phone from deep sleeping once they are used.
The two fixes I've found:
1) use a compatible charger. Even if you just plug it in for a few minutes, it seems to reset something and cause it to sleep again.
2) restart the phone. This lets it sleep again.