As I have already mentioned, I'm monitoring the battery and no current drain occurs after stopping the engine and closing the doors.
I don't remember if I have double locked the doors at that time.
I'm monitoring the battery since that event and seems to be OK. It have been almoust 3 weeks since that and didn't happen again.
The car doesn't have any extra consumers plugged permanently into the rear power point.
I hope it will never happen again.