Yeah hopefully the glitched achievements fix themselves. I don't really care about the mission issues (now), although when I'm stuck slogging through things LASO I probably will

On the plus side I think co-op felt a lot smoother in CEA than it did when we played on 360 between Six and I. Only had one desync message pop up, and unlike previous times, it didn't mean we both got booted and the mission ended.
Random glitch, however--for me at the beginning of T&R I popped out of the Pelican, but I stayed in "cinematic mode" in my view, unable to shoot and move, and only able to look around. According to Six I was running around like a crazy person on his screen though

Did give me time to use the insta-switch on the Chief model, and it's interesting--the Chief's helmet is crazy elongated in the original game, and basically every version of Mark V since then has squashed it slightly (including CEA.)