Firing and rehiring them fixed this bug for me (though I note that they didn't actually stop having the effect on security and prestige they're supposed to).
I did a brief glance around on the Steam vs GOG front and found this:
http://www.gamasutra.com/view/feature/186940/defenders_quest_by_the_numbers_.php?page=1
Obviously this won't hold true for all games, but for that game Steam was ~59% of sales while GOG was ~9%