Achievements halo 3

Games Halo: The Master Chief Collection
1

hello guys, i have a problem, I completed the halo 3 heroic difficulty, but the achievements are blocked at 88%.
To you this problem?Solution?

2

I checked your service record and it says you have not completed floodgate. I don’t know why these things happen though.

3

so I have to redo the mission?

Edit : I played the mission, I still have goals blocked …