my achievements stoped unlocking. a few are at 100% but are still locked. why?

Same here I just collected all Intel and achievement says 100 percent done unlocking I also did the troubleshooting from the Xbox website and deleted and reinstalled my profile the website says allow 72 hours to go by so it can sync up so I’m just hoping it works

That happened to me with a couple achievements for the Glassed mission. I looked on Smartglass a few hours later, it showed them in my recent news or whatever it’s called.

I have seen where this happened to me on halo the master chief collection and eventually the achievements just randomly popped

Xbox one achievements have been doing that since day one.
I just completed Reunion on Heroic last night without using a Phaeton, and didn’t unlock “Take a hike”. Games just as broken as every other Xbox one game.

This happened to me before in a few games (like Titanfall) if I logged out of my profile at the game menu and sign back in it usually works.

With Campaign skull and intel achievement, try to retake some skulls or intels until you get the achievement. That worked for me with the gravelord achievement (I took the IWHBYD (Osaris) skull again)

Settings from the main menu…mine did the same thing