Upon entering into the player profile, while in a custom map or proving ground, it registers the back/esc key press by showing the button in the bottom right being briefly highlighted, however it doesn't actually exit.
The only way I could exit is by closing the entire game (Alt-tab, then close the window).
I can repeat this every time I enter into the player profile. It appears to be a regression as v6.0 doesn't have the same issue as the PTS 24/07 version.
I'm aware that the profile is largely meaningless at the moment in the proving ground or custom maps. I only came across this as accidentally hit the down arrow on my steering wheel (Logitech G29) while driving and got stuck in it.