Montana 7x0 continues turn-by-turn in charging only mode

[ConiKost]

Just noticed by accident. Using firmware 19.20.

Needed settings:
* Setup -> System -> Advanced Setup -> External Power On = Charge Battery
* Setup -> System -> Advanced Setup -> External Power Off = Turn Off
* Put Montana in AMPS mount with power cable

1) Turn power on, so Montana will power on and go into charging only mode
2) Press power on
3) Start any simple A->B route
4) Start driving on this route
5) Turn power off, so Montana will power off
6) Turn power on, so Montana will power on and go into charging only mode

If you continue driving the route, Montana will still output via audio turn-by-turn.