Car suddenly dead, then back?

Bad Boy

I got in my car, everything was normal and fine, and drove to a store.
When I came back to my car, I pushed Start, and nothing happened. I noticed not even the dome lights or interior lights were on.
The car was completely dead as if it had no battery.
But I knew my battery should be fine as it is only a couple months old and alternator seemed fine last time I checked.

As I was waiting for my brother to come pick me up, I decided to try and start the car again, but first I moved my door a little and noticed the interior lights finally decided to kick in, car started normally.

At first I thought it might be a the starter, but realized not even the interior lights were on, so it must be electrical. I ruled out a steering lock issue due to having it fixed via recall before anything happened.

I'm thinking somehow the car failed to get a battery connection? Because when the car started, my radio and interior light settings all reset...

Any ideas? and if it is battery related, did me moving my door a little trigger some sort of sensor, or pure coincidence?