Rear Door Locks (or unlock)

[B'ham G90]

I have the doors set to lock automatically, but frequently put packages or other small items that I don't want to put in the trunk in the back seat floor board for quick trips. When I get where I'm going and try to retrieve my package, the back doors are locked. Even with the key in my pocket I can't open the rear door without re-opening the front door and hitting the unlock button. Double-tapping the door handle doesn't even seem to work (like I do initially approaching the car and want to unlock all four doors for passengers). Any Ideas?
2018 G90 3.3T
I've owned it for just over a year, but can't get this figured out.

 

[CJL]

I have the exact problem with my 2017 G90. Happens 90% of the time as you describe, have all the settings correct, and my backseat passengers are locked in most of the time. Of course, this random event never happens at the dealership. Hoping someone has a workaround. Thx