I just solo'd the campaign but it says I only have 3 missions completed on legendary on the challenge. But when selecting the missions it says that I have beat them all on legendary. Ive been hooked up to XBL the whole time.
ALSO, if I do have to go back and beat them, would anyone want to join me so I wont be so damn tedious? --- http://i.imgur.com/YYSWz.jpg