I am going to guess on this, seems like the reconnecting of the car battery clears some stored fault in the computer.
I had a Nissan that if engine temps rose too high the car would stall and not restart until cool. So maybe there is a temp sensor on your car around the radiator or heads that is defective.

But wait until a tech posts, nothing like the familiarty of working on a model to find a cure, and having the Mercedes diagnostic computer.