Matchmaking ban for no reason

So I got on for the first time in almost a week today, to see what weekend playlist was there. It was a crappy warzone one again, so I decided to play fiesta.
About 5 minutes into the game, I was returned to the lobby and got the message ‘your fireteam has changed, you have been returned to the lobby’
I was like “well that’s annoying, guess I’ll join another game.”
But no, I have a 20 minute ban for quitting.
What the hell?

Please use the ban thread in the Halo 5 support forums
Official Halo 5 “Why was I banned?” thread