Yes I know this same bug has been reported before back in version 0.6.6.1. But it still hasn’t been addressed in any patches or anything. Anyway sometimes when you join a game lobby (For example a lobby in little crusaders as demonstrated in the original post) the waiting for players menu doesn’t appear, and music doesn’t play. You can’t ready up in this state and you can just look around the map. The effects stop after the match starts but (If you have 4 players in one match) if you don’t have more than 1 person able to ready up, you’re going to be stuck there a while.
Can confirm, I still get this as well. Sometimes, I can open the main menu (where my name is “[UNKNOWN]”) and disconnect just fine. Afterward, everything is normal.
Other times, I cannot open my menu at all and I have to ALT-F4 to close the game.