I’ve been going for the Smooth Operator achievement and I’ve noticed my progress has not been saving under the “difficulty completed” section in the Spartan Ops menu for all the missions I’ve done. I’ve got all the way to 2-1 and the achievement counter is at 12% which would roughly translate to 6/50 missions, and a while back my friend and I did up to 3-1 on legendary and Icarus/Hazard Pay/Term of Enlistment/Feet First are all at 22% which would be 11/50 missions. The progress shows up until I turn off my console and come back to it later.
Edit: completed 2-2 and the Smooth Operator counter is at 14% so at least the Achievement progress is tracking