Occasionally i have been experiencing a bug where upon joining a custom multiplayer game, the actual 'match' lobby won't load and I'm left with a black screen with the blank map in the middle.. however when i navigate away from the screen and go back to quick-match or any other tab, including the 'browse' tab it's all reset as if i never joined the match. The problem however is that i am actually IN the match lobby, but can not view the lobby, leave the match, or do anything to do with the match. (You can't even really tell you're still IN the match lobby at all). The match then launches and I'm taken to the pre-game loading screen and the match starts from there as normal.
Another separate bug i have experienced and seen others in game experience, is the in-ability to click the 'start match' button for custom matches for some reason as a match host. The 'start game' button remains greyed out with the lock symbol on it, and the match cannot be started at all. The only solution I've found is to completely leave the match and everyone join a new one.