Tesla Model S, Signature Firmware v8.1 (2018.24.1 12dd099) While doing chores I visited the Post Office to deposit a letter. This branch had a drive-by, and due to my elite skills, I missed the post box and the letter dropped to the ground. I placed the car in Park, unbuckled my seat belt, cracked open the door, leaned out to grab the letter and placed it in the post box. I then returned to sit upright, closed the door and attached my seat belt. My driver's display now stated "Car Off", and it "Could not start again without powering off". I used the center display to Lock and Unlock the car. Nothing I opened and closed the door. Nothing. I had to physically exit the car, lock and unlock the door and then re-enter before the car would allow me to drive away. Much to the amusement of the three cars waiting behind me, observing this "high technology" car of the future. I think the car was confused with my half-butt-in-the-seat-open-the-door-but-not-get-out maneuver. PS: I still have the music "Load Error".