. . . same issue happens to my wife today.
After questioning my wife she remembered, that she has forgotten during the drive to disengage the start/stop function.
When she arrived at the parking lot, the vehicle goes into automatically in the „stop"-Modus and she put the gear lever in the „P" position. After returning to the car, the Grenadier failed to start. She left and locked the car and went in the supermarket for further purchases.
When I arrived 20 min later and tried starting the engine, everything was fine, the Diesel started immediately.