What's wrong with my gameplay?

Good night dear!
I ask you guys for help about my game Halo 5.
I finished the campaign on Legendary difficulty alone. I do not know why, my save game got a problem of information … Some quests are as if they had not been thrown … but as for you guys site is information from 15 completed missions? In the Grid achievements, the last one was released, it was to complete the mission 14. When actually finished all … Please help me.