Hi 343. Firstly, I would like to say, I love your work, and am excited for the things yet to come. I am exceptionally pleased that S.W.A.T. has been added to the online multiplayer playlist, and have been enjoying the quality of your re-mastered games. That said, I’ve experienced an issue that I’m not particularly happy with. I have played up to the mission 343 Guilty Spark in Halo CE, and beat each mission on solo legendary. The first two missions I received credit for, and it shows I’ve done them on legendary. From The Truth and Reconciliation until 343 Guilty Spark, the game has not given me credit for completing those missions at all, let alone that I did them on legendary. I have achievements specific to the missions to prove that I did them, but for some reason, the game doesn’t acknowledge that I have beat them on legendary solo, and hasn’t given me the achievements for beating those missions. This is a frustrating situation to be in, to say the least. I haven’t had any issues with the other games I’ve played and beaten, it just seems to be Halo CE. If there is any way you can rectify this issue/problem, and possibly prevent it from happening in the future, that would be greatly appreciated. Thank you, and I appreciate your help, in advance.
Also, a side note, unrelated to my issue above; I love swat, and would love to see ranking on it in the next update, and maybe even some big team. I know I would be really excited to see these things implemented into the next update. 
thank you.
You know what? This recently just happened to me on my main account. I played the first 2 missions of Halo CE on Legendary and took a break from a while. I came back to finish off the campaign, hit resume, and carried on. The difficulty was still the same, and had a tough time with enemies as you would on Legendary difficulty. But after completing Assault on the Control Room I backed out to do some multiplayer, only to find that I had only been credited with completing the missions I just played on Normal instead of Legendary. I even went back to the campaign menu to check and it was still showing Legendary as the set difficulty. So from the look of it I have to play the last 3 missions again.
My guess is that this is yet another bug caused by fixing other bugs in the game.
if I beat all of them on legendary, but I don’t beat halo 3 odst when it comes out, would I still unlock halo 5 helioskrill armor
Well then my next question becomes then, will I receive the credit for the missions when they do fix this bug? I love halo’s story, but its hard enough to beat on your own once. I’m not even sure I want to keep playing Halo CE, until I know this bug is fixed, and I maybe even get credited for the missions I already did, just yesterday. I really hope they do this in a timely manner.
Getting legendary complete on each game is tough enough, especially when solo, without not getting credit for the missions I do.
Not to mention, you at least got the missions credit on normal. mine doesn’t even acknowledge that ive don’t those missions. period. its really disheartening.