I guess after a game, the upper-left button is there to load the screen of the post-game results, as long as you didnt leave the (post)game.
Bug 1: If you dont leave the post game, but open another match-summery, then the upper-left button always brings you to the last viewed match and NOT to the postgame screen of the game you didn't leave yet.
Bug 2: If bug 1 occurs and while you still didn't leave your game; you manualy load the game results (go to your profile -> select latest match) of your active post-game, all the hero-xp and relic-updates will be played agin, before the stats are shown. it's the very same procedure that happens right after the game ends.