Halo 4 Requiem Achievement Not Unlocking

I don’t post too often, so I’m sorry if I’m not doing the right thing at the right place. But I’ll get on with my problem. I’ve completed every single mission in the MCC on legendary, however, Requiem’s achievement is not unlocking. I’ve checked my service record on here, and it says the mission is incomplete. When I check my campaign stats on MCC, it also says the mission is uncomplete. Though in the menus I have the legendary badge displayed for the mission. This is very confusing, and I know I’m not the first to suffer from these glitches. I really do not want to replay the mission, as completing all 4 campaigns within a week’s time takes a serious mental toll on you. Thanks for any assistance, ~ Amphh

(Note, the ‘Requiem’ achievement does not say “Done… Unlocking”.)

Just replay Requiem until it registers and unlocks the achievement. Its literally the only level not marked as complete on your service record here. If you speed run it using either Naked Eli’s guide or Halo Completionist you can have the level done in under 20 minutes. I know it sucks to have issues like this but at least its only one level and your going to have to redo it because nobody has ever gotten somebody from 343 to just “unlock it” for them.

Thanks for the response man, now it’s time to force myself into playing it.