I’ve been playing the campaign missions since launch on legendary and collecting skulls and terminals but only a handful of them have been unlocking for me. When I go to view them it says “Done! Unlocking…”. But it’s been saying that for the last couple of days. I thought it was just my xbox/game that was messing up so I tried quitting out of the game and restarting it and also power cycling my xbox to no avail. Thoughts on how to proceed?
I’m having the same problem
They are aware, and the problem is being looked into.
Also, there’s already a thread about this. Can’t paste the link for some reason with my phone, so you’ll have to search for it. 
Thanks for the heads up. I wasn’t sure if it was just me. I guess I didn’t look far enough back to see if anyone had posted anything about achievements. 