Platform: PC Steam
What you were expecting to happen, and what actually happened:
I had just completed a task for Chapter 9 of the campaign, and it appeared that I still had one more task to complete, but I was not presented with a new one. I know I still had more silver and gold tasks to complete, but it appears I have run out of bronze ones even though the counter is off by 1.
How often does this happen? When did it begin happening?
Has only happened once and will probably only happen once, since this is the only instance of this opportunity to happen in the game.
Steps to make it happen again
Tried exiting the campaign screen, and also Gems of War itself completely, with no update to the counter.