I think the car can sense if the fob is within range. So if you sit in the car, I would assume you have the fob. If the fob is in the car, the lights won't go off. Once the fob is out of range, the timer kicks in and the lights will shut off based on the settings you have.

 

I think it might be due to the door not opening. My friend's GM Suburban's radio will continue to play, if the car is off and the key is removed, until the door is opened.
Not sure if it's the key fob, but there is an easy way to check. Open the window and hand the key to someone (or get out of the car and stand within range for 30 seconds).
I'll bet the lights off-timer doesn't start until you open the door.
Presumably, the lights-off feature is designed to allow you to walk away from the car with illumination. I guess the car figures you aren't walking away until you open the door and get out of the car.

 

I think the lights-off timer only starts operating after all the doors and trunk have been closed, not opened.

Stan

 

I have closed and locked the car but left the trunk open to empty it and the lights stay on until the trunk lid is closed. I find it handy as the car lights up my outside staircase.

Barb

 

My car is set to 0 sec delay shutoff on auto. The lights go out when I open the door.