My Career Statistics Don't Reflect What I've Done.

I’ve beaten all of the campaigns by myself and on Legendary. I even just finished my rerun of the Reach campaign and it instantly shows that I’ve completed it. Yet, when I looked at my stats today in my player details, It doesn’t show that I’ve completed Halo 3 at all. It says my highest difficulty completed is “UNPLAYED”. I have the achievements to prove that I’ve done it, I have the achievements from the campaign as a whole, and I have the nameplate signifying I’ve done as I say I have. My service record shows the completion of each level. I don’t mind replaying Halo 3 again (I already have to for playlists), but I’d just like the effort I’ve put in to be reflected in my stats. Does anybody know how to fix this?