I'm curious as to what actually constitutes as a Leaving Penalty.

One night I tried queuing for a match and nobody, not even the CPU controlled AI, connected. It was completely messed up. The Character Select Screen showed nobody and I couldn't even choose a character. By the time I got "into the match" I was staring at the battlefield with nothing on it and it said "Disconnected."

I did what any sane person would do... instead of watching paint dry, I left. Well for doing so, I got a Deserter Penalty.

And just recently I had completed all the playable content. Nothing more could be played... Mission was completed and I wanted to move on with my life. The post game shenanigans take such a huge chunk of time I was just tired of seeing them. But apparently that got me a deserter penalty, as well. Even though all playable content was finished.

What gives?