I Beat Halo 4 On Legendary But Online It Says I Haven't

[Akali]

it would be good if they fix this because people can get the hardest emblem (laso emblem) through a glitch in waypoint and they really need to fix their game and codes

[тυcкєя]

Not entirely sure why, but make sure you have completed all of the missions. If not, it wouldn't hurt to do them again. Because I thought the campaign was creative, fun and a little easy. But some parts were hard. Hope you can figure it out !

[Buns]

it would be good if they fix this because people can get the hardest emblem (laso emblem) through a glitch in waypoint and they really need to fix their game and codes

They can't "fix" this because there is nothing to be fixed. 

[Ghost Recon]

If I am not mistaken you have to be online to get the Armor, since the Campaign has Commendations that you need to complete online.

[343HaloUniverse]

The same thing happend to my self I had to sadly do it again online then I got it I was shocked though, but good luck if you get it and bad luck for not getting it