I suspect the MM problems aren't build related but server related (MM server) or possibly a new server is online that has a name that is causing some sort of parsing error. Hard to believe that the internal team tested this for a week and then the public tested 493 for a day and no one saw a CTD. Not to mention the CTDs didn't get reported until the past few hours. The join button not showing is another problem though. That I suspect that is a build issue. Let's see what happens in a few hours when the devs are back in the office.