2 of these for me were bugged (Warlock and Hunter) and did not unlock, how I got it to pop was by pressing start in game (character customise) then press RB twice over to settings and go to log out and switch profile then log back in with your profile and pick your character, I picked one of the ones that glitched and both unlocked for me that were glitched.
Thumbs up if it works for you too