I don't know if anyone else was affected by this, but there was this wierd bug that used to slam me, back when the critical missions were released all at once in one bundle. If I helped someone else with a crit, my crits would get bugged so I couldn't do the next one. I'd go to every single district, but the crits would never, *EVER* show up in my mission window. My rep climbed pretty fast since when I started, I ran all my missions on "Easy", so it wasn't a rep problem. I CCRed about this on numerous occasions, but got no results.
But now... I ran an 8.1.2 or .3 mission with a buddy a few weeks ago, and when I came back from my enforced hiatus, I expected to have lost my crits. But to my surprise, I was able to run all but the crit that I'd already done with my friend. Whew... that's a welcome relief.