Start with checking if the actuator in the rear (cargo) door is functioning properly. Sticky handle not returning down or other issues.
Mine is to the point the key works in the drivers door but I need to cycle it 3 times to unlock the other doors., they go up a little each time.
Seems the Pax door does not signal the control unit or something, been a long time since I tried it. The key will not open the other doors from the pax side.
My remote did not like being in my pocket when I seem to have gone swimming out of my canoe a decade ago so I can not offer allot on it. but,
When using your remote, watch all actuators. might be one door is draggy such that it does not signal the control unit properly. They all must freely unlock it's door or an error happens.