Hi 343! So, after all of the reports of broken achievements, I tested out a few with friends, because I didn’t have any DLC achievements except for two, which my friends tested out themselves. There are 5 broken achievements:
Bird of Prey
Pigs Can Fly
Clever Girl
I See You!
Ashes to Ashes
The only one that unlocked for one person only was Bird of Prey, but it didn’t work for the rest of us. The rest were not unlockable.
Hopefully this will help pinpoint the problems with these Halo 4 achievements.
~Cizlin