It seems that for higher level missions, the system sometimes crunches numbers for too long, and Facebook times out. The higher level the mission, the more likely this will happen. (To test this, try running a mission in one of the early locations and see if that makes a difference.)
I'm traveling right now but will take a look at this when I get back.
For those who are seeing CR regen slow or stop, you've encountered the anti-cheating mechanism in the game. If you reload very quickly, it's possible to conduct missions over and over, sometimes even after you run out of CR. (It will go negative) A few months ago I changed the game to detect this situation and penalize the player. Basically when the game detects this problem it pushes out your next CR regen based on how 'bad' the cheat was. If you got away with a lot, it might be a day or more before you see your next point.
Now, I'm not trying to insinuate that folks who have been dinged by this are cheating. If you don't know how the system works then it's more likely you're just using it this way and didn't know it was a problem. In short though, reloading the page before the last load has completely finished could trigger this event.
Hopefully that makes sense.