The difference in behavior is dead simple. When you get out to open the gate, you are putting the vehicle in park. When auto start stop kicks in, and the vehicle is in park, it shuts the car off (which is nice usually when you're parking).

But sometimes, I would bet the temperature, coolant temperature, or other conditions are preventing start stop from kicking in which means the Defender stays running.

When you are just driving around, with the transmission in a D or S or whatever gear mode, the auto start stop kicks in -- but it doesn't shut off all the electrics etc. That only happens when you're in park.

 

That may be the case on some models. In the hybrid there is no start/stop function to turn off though. Where the start/stop button normally is there is just the button to control EV settings (hybrid,EV, save). The car does what it wants regarding shutting off engine.
So as I mentioned I experience the same as threadstarter and Britcars but have thought it to be a hybrid model thing.
Took me until now to realise I can bypass it by turning the engine back on with the door open.

 

I think it has something to do with location services/navigation (if you're not talking about the eco auto- start/stop). For example, I play golf 4 days a week, when I pull into the parking lot at the golf course and stop the car, it shuts off. When I drive home and park at my house, it shuts off. But as the original poster said, it doesn't happen 100% of the time. I've noticed when I look at my map, even if I haven't asked for directions, the car/car play is assuming where I'm going, and has directions on the screen.

So maybe you can check your trip settings or navigation.

 

I think it's a "feature" related to navigation/location awareness. Sometimes, when I park my car somewhere I frequent, the car shuts off. I only really notice when I push the button to shut the car off, and it turns back on, or notifies me that I need to put my foot on the brake if I wanna start it., I've only ever noticed it at three locations: golf course, gym or home. But it doesn't do it every time. I haven't really tested it, but I'm guessing that If I deviate from the normal route (previewed in the navigation app) or it doesn't shut off when i get where i'm going.

 

Hello. I think it happens in my car when I turn it on through the app. Then when i push park it shut off. 🤷‍♂️

 

This commute option make a lot of sense. thanks

 

If auto stop/start is active and you have come to a stop and put it in park and engine is still running, you can unbuckle and open door and it will not shut off.
If auto stop/start is active and you have come to a stop and put it in park and engine is not running, you can unbuckle and open door and car will shut down, thinking you reached end of journey. It is like a convenience mode thing.
If auto stop/start is active and you have come to a stop and not put it in park and engine is not running, you can unbuckle and open door and car will shut down, thinking you reached end of journey. Likely start beeping as well and again, it is like a convenience mode thing.
If you need to do a quick hop out-hop in when engine shut off, maybe put on the aircon/defrost/or whatever that draws from battery to stop auto stop start to kick in?