Achievements not unlocking

Since finishing the campaign with my peers on Legendary, I nor we have been able to unlock any ‘par time’ achievements. Initially, I thought this was difficulty, as we started on normal, but we later did Tip Of The Spear on Heroic and I just now have completed it Legendary Solo, 12:29, and I still am yet to receive the par time achievement.

Is this a wider issue for anyone else?

I have the Steam version of MCC, and I do not have either the Steam or Xbox achievement for Nightfall, but do apparently have the achievement for TotS 3 days ago.