Unstable Iso-8

Not sure of this is the right forum but I'll ask anyway.

I have completed all of the missions in unstable iso and all but one ( Greenland Ops) say they are locked.

Is this a bug or is it meant to be like this?

The reason I ask is that I can see people on the ladder with 4 and 5 hundred iso so if it isnt a bug they have been playing the same mission a massive amount of times.

Just curious and really wanting the other rewards from the other missions.