Edit: Problem solved! All I had to do was shut down the game and restart it. I assume signing out/changing characters would've had the same effect in case anyone else is having this issue. Either way, this is definitely something Bungie should look into, becuse I don't think this was intentional. Thanks for the replies! So I finally decided to actually work towards Mountaintop, and it went pretty well with Mayhem/Momentum Control. I got the triumph complete, turned it in, and... Nothing. The triumph didn't count towards the quest. The only thing I think could have affected it was that I completed the kills etc. on PS4, then I accepted the triumph on Steam. I didn't think that would be a big deal, and I still don't. I've included two images in an Imgur link attached to this showing that I do have the triumph and the quest still isn't complete. Is this a known bug, or did I do something unique? I looked on the first 3 pages of the help forum here to see if others were having this issue, but I found nothing. If it were possible to search the forum here, I would've looked more.