Last night I set three challenges (it throws an error if I try to make a 4th). One was for 276 kills in MM, one for 250 headshots in MM, and one for 8 wins. They were all set for 3 hours. I played swat for the next three hours and averaged somewhere around 15 kills a game. But even still now, it says that I failed the headshots and kills challenges, with 146 kills and 113 headshots. I looked on bungie.net at my recent games, added all the kills together, and got 354. It’s been around 12 hours since I completed those and waypoint still hasn’t updated past there. Is it eventually going to update or am I just screwed out of the credits I earned?
Sounds like you were so called ‘screwed’ out of the credits, either way, it would be simple to just set them up again and re-do it.