Halo MCC - Spartan Ops Episode Completion Achievements Not Unlocking

I am currently nearing completion of Spartan Ops solo legendary, but three of my episode achievements have not triggered. Specifically, Catherine, Scattered, and Invasion. My progress is shown correctly in game, but not represented in the Xbox achievements. For example, the Catherine achievement says that I only have 80% completion, despite all chapters in the episode showing that I have done them solo legendary. The other two show even less progress, both only 40%. Usually I would wait to see if the achievement was just being slow, but Catherine is for Episode 3 and it has been days. So far, I have only done 7 out of 10 Spartan Ops Episodes. Of the 7 completed, I only have 4 of the Episode completion achievements. Another thing is that I would have kept playing without issue, as maybe the solo legendary achievement was not tied to the episode achievements. But, I'm not sure that's the case because Smooth Operator only shows 60% progress. 35 out of 50 total chapters is at least above 60%. I have also replayed the chapters I thought were causing it, but it hasn't worked. I was also confused about whether I should ask here or go to halo waypoint support? Since it shows that I have done it in the game, just the achievement not working. I'm not going to complete any more Episodes because I'm not sure if it will or won't count. Maybe there's something else I'm not aware of? Not sure, but help would be appreciated, thank you.

:)