Every 622 that is in standby mode over night "reboots" to updat info. If you are not shutting off the unit over night then what maybe happening is that if you are using it a 3 in the AM then go to bed. It will go into stand by mode 4 hrs later. When it goes into stand by it will reboot at that point. So if at 3 or so you have just switched channels it is very possible that it will reboot a 8 am. There is a setting that is called inactivity standby that is set in your menus. It can be set for 4,5,6,or 8 hrs. It is possible that this may hve something to do with when yours is rebooting in the morn. If it has been set for say 8 hrs then if you stop watching at midnight it would be doing it's reboot at 8 am.
Mine are both powered down, and have been every night since we owned them.
I specifically have them set to 3am and 8am, so they do their updates/self-starts during non-usage times. They are both still set at the default 4 hour inactive mode. I am always using the 3:00am set receiver until 1:00-2:00am. It always performs the scheduled update at 3:00am.
In fact, regardless of the inactive setting, you can look at the current time, (Ex-9:10PM) immediately change the update time to 2 minutes later (9:12PM), and power off the receiver using the remote. It will update/self-start at 9:12PM, just two minutes after the receiver was active. It's a way you can 'force' a needed update/download.