REJOIN MATCH appears without starting game

Me and a few others I’ve spoken with are receiving the same error.
We queue for competitive
Match is found
Rejoin Match option appears
Error message in bottom left shows “failed to connect to server”
This started happening when Junkestein rolled out.

I am having this exact same issue on Xbox One. It happened twice today, once while in a group and once while I wasn’t. 100 SR lost, and a 30 minute ban after the second one. Talking to online support chat right now, and they said they didn’t know about the problem. She told me that if I kept playing and it happened again, I would potentially banned for the rest of the season and they would not be able to lift the ban. That is a crazy policy for something that stems from their software. I think they need to put an in-game message warning users of the SR loss and potential bans immediately.

It’s now occurring to me how many games I have played in the last few days where a player from my team or the other team quit early at non-tilting, inexplicable parts of the game. This seems like the culprit.