I just bought my xbox One a few weeks ago and have been playing through The MCC, which I have been very much enjoying. Today though, I was playing Spartan Ops on Legendary and did not receive the "Catherine" achievement for completing ep3. All of the chapters show that I completed them on legendary, but the achievement will not pop up.
As I do not want to do it all over again, can you please tell me how to fix this?
Also, the achievement itself, says that it is 80% complete.