I have multiple triumphs that will not complete no matter what i do. I am only certain of 2 that are still bugged at the moment. Downfall and No time left story mission triumphs. I first beat lightfall with my warlock solo, on legend. then some missions on normal, then i fid legendary again as a duo with my friend as my hunter. I have 2 full campain clears so these triumphs should be checked off, and im sure others arent working either but i never realized at the time.