A friend and I were trying to start an arranged team game. When I hit the button to join the queue I was given a message saying we failed to join the queue. My friend got an 'unknown error' message box. From there we had trouble joining any game and talked for a bit joking about how glitchy the game can be.
I logged out and logged in later only to find the game has been left, reconnect? screen waiting for me. I joined the game way behind (with a random character of course) and my team (without my friend) went on to surrender pretty quickly.
It's a pretty bad bug for the game to put you in a game you had no intention of joining and you never even knowing it.