Messed up LASO playlist

So I’m certain most of us are aware that Microsoft had some issues yesterday as Xbox live was down for several hours. Unfortunately, I was one of the players grinding through the LASO playlist for Halo 4 during the midst of the “shutdown.” Well ironically, I was playing the mission shutdown and was on the literal last second of the mission as I jumped off the ledge to finish it and trigger the final cutscene. With my luck, the game had closed mid-jump and displayed a message saying that I needed to be logged into Xbox live to play the game. Yet, I immediately loaded MCC back up after I closed the message with no issues. I checked the progress on my playlist only to see that it never counted that I essentially finished the mission. I’d be forced to do it all over again. It just seems like a big slap to my face. Everything was running just smoothly before and after, so what was the need to close the game down?
Regardless, the other friend I was running the mission with managed to stay in the lobby somehow and actually finish the cutscene and have the progress count on his playlist. So I joined him and figured we’d load up his playlist and continue from there to see if it rectified my playlist—either it’d give me the progress or just say I still need to load up shutdown and replay it. Only upon exiting, it updated my playlist with a checkpoint at the start of the “Composer” mission but still counted the previous “Shutdown” mission as incomplete. So now, not only was the mission I just finished counted as incomplete, but I can’t even go back and replay it since we now both have a checkpoint on the next mission.
I understand that this problem didn’t necessarily originate directly from 343 and the MCC; however, it does seem a bit unfair that I’m sort of screwed here. I’m missing progress, I can’t go back to even try to get that progress again, and the only apparent way to fix it is for me to continue playing through the playlist and finish it, only to be sent back to the beginning of the playlist and have to replay essentially the first half of the campaign just to reach the problem mission so I can, AGAIN, play it and hope nothing bugs out again on that run. It’s a whole workaround just to finish one mission I already did, you know?
Given the circumstances, it kind of raises a few concerns for me: 1. Why is there no mission select during a playlist to avoid these kinds of issues? 2. Why is it that there aren’t really checkpoints that genuinely save your mid-mission progress if you exit out? I.E. Sure my game crashed at the very end, but how is it that the other individual halo games can provide a checkpoint for you to resume on (presumably just a few moments before that final leap) while the MCC simply says you cannot continue from said checkpoint, you’d need to restart the entire mission and play it again? This isn’t the first time I’ve necessarily lagged/crashed out of mid-LASO but it is one of the most irritating and inconveniencing times, thus my inclination to actually sign up on the support page here and speak up.
Now I’m not necessarily sure of what mythical voodoo powers 343 has, as I’m sure they can’t rectify EVERY problem that ever happens since some are just out of their reach—pun intended—however, I do feel there should be some capacity to either rectify that mission not counting as completed or, in the worse case, at least grant me that checkpoint of the shutdown mission back so I won’t have to redo nearly the entire playlist again just to finish one mission (We all know how tedious, difficult, and lengthy each individual LASO mission can get, let alone the entire campaign). Furthermore, if I can receive an actual explanation about the reasoning for the previously mentioned concerns or, in a better case, a re-evaluation of them, it’d be very much appreciated. I’m sure the rest of the community would appreciate it too as it makes all of our lives less complicated.
Hope to hear from someone soon on this! Thanks.