Good morning Jason,
I have a 2006 MZG too. A very fine machine it is too.
I don't have it with me at the moment so cannot go out and play !
From the JPNZ manual I learn there is a anti theft security feature that may be causing the problem !
The feature prevents the lock/unlock button being used through a partially open driver window !
There are several sequences that cause this to happen. (If necessary I can advise you of these).
As the drivers unlock button works, this doesn't seem to be the problem.
Also, as in the Rav video, the lock behaviours can be programmed.
These are:
1) Shift linked auto unlock.
2) Vehicle speed auto lock, my setting, and the default setting. Your setting.
3) Drivers door linked unlock.
As P doesn't unlock all your doors, option 1 is out.
If driving off doesn't lock the doors at 20kph (fault aside) option 2 is out, but it does !
I wonder if the system has become confused.
If option 3 is set, try to switch off the ignition and open the drivers door within 10 seconds, that should unlock all doors.
As a personal safety measure, I would not want my doors to unlock every time I stop, only when someone needs to get in or out.
I assume this is the function you want. I would then press the unlock button.
Changing this setting is as per the Rav video, but pressing the lock/unlock drivers door button to UNLOCK for 5 seconds.
This should set the system to default, which, confusingly, yours seems to be set to !
As I say, I don't have access to my machine otherwise I would go and play.