Update: We found that when you hit Search Again or Create a Group in a game lobby, the host sees you as disconnected and can add a replacement player, but you still see yourself in the lobby. Even if the game is canceled after the host failed to meet the five minute limit, you still see yourself in the lobby. This may explain why some of you were "stuck" in a lobby with a host who did not tee off.
We will work on a fix, and in the meantime if you go into a group you don't want to be in, a work-around is to close the game client, wait 5 minutes, and relaunch the game. We apologize for any inconvenience.