If you finish your Tavern Brawl game after the brawl hours are over, it will leave you with a glitched UI. You can't click on any buttons and are forced to restart your client in order to fix this bug. Upon completing the game, it should display the correct UI, tell you that the brawl hours are over and kick you out into the main menu (as it currently does if you stay in the brawl screen after the brawl ends).
If you finish your Tavern Brawl game after the brawl hours are over, it will leave you with a glitched UI. You can't click on any buttons and are forced to restart your client in order to fix this bug. Upon completing the game, it should display the correct UI, tell you that the brawl hours are over and kick you out into the main menu (as it currently does if you stay in the brawl screen after the brawl ends).