Egregate

When I restart the Asus Tinkerboard R by unplugging power, the clock is set to build time, and there it remains. The log says 2017-08-05 11:00:19.785 521-521/system_process I/AlarmManager: Current time only 1501923619785, advancing to build time 1598248575000 2020-08-24 07:56:15.005 521-521/system_process D/SystemServerTiming: StartAlarmManagerService took to complete: 12ms ... but the correct datetime is never set. When I reboot the system by adb reboot, the time will be set correctly. Why is this so?

I restart my Tinker Edge R by pulling the power supply and re-inserting it. However, under Android 9 at least, things do not start ok this way: My LTE connection does not initialize, so I get a unit that is not connected to the internet. If i instead do "adb reboot" from an attached PC everything starts up again ok. Why this happen?