Halo 2 Gravemind legendary achievement not popping

yea... i've done all that.. it says I havent even played that level.. i'll wait 72 hrs but ifs not popped i'm selling it all. halo 2 campaign on legendary is super hard as it is.. i am NOT doing it a second time

Hi, I hope you're doing great out there despite the issue that you're experiencing. I am an Independent advisor and I am here to help you in regards to your concern.

Please make sure that you’re connected to Internet by following the steps below:

Settings > General > Network Settings > Test Network connection.

If successfully connected it may take within 72 hours for the achievement to poo-up. You can also check this link for the troubleshooting steps: https://support.xbox.com/en-US/help/games-apps/...

I apologize for the trouble and hopefully, after 72 hours you’ll see the achievement on your account.

Im still having problems where my achievements wont pop after completing them. I just beat HALO 2 on legendary, got all the toys, and all the skulls. The skulls achievement popped but non of the others did. The two toy achievements say they are unlocking
on my xbox one but its not even showing that I beat HALO 2 on legendary and all the achievements that go along with it.

So a year later, and achievements still fail to pop

In halo 4, completed 3rd mission solo on legendary in June 2015, and it showed it completed solo on legendary properly but didn't pop the achievement for that mission (which doesn't require any particular difficulty).

I waited 5 months and it never popped.

Then last week I did all the rest of halo 4 on legendary co-op and the achievement for doing all missions legendary didn't pop. So had to rep,ah mission 3 and it popped. BUT I SHOULDVE GOTTEN CREDIT THE FURST TIME WHEN I DID IT SOLO!

I wish 343 would fix these problems!