Hey there, I just finished Reach on Legendary Solo. I didn’t get any “Finished the Campaign” ones. Upon looking, it says in my Achievements, I’m missing Long night of Solace and maybe another. MCC in game displays I’ve finished these levels, so why won’t my stuff pop?
Upon looking at your Service Record here on Waypoint, the campaign mission “Tip of the Spear” didn’t register. Completing that mission again should unlock the achievements.
It won’t unlock because the achievements are tied to your stats on Halo Waypoint, not your in-game stats.