I was signed into XBL the entire time and I even got the achivements.
But, I went to my stats and it still shows Heroic in progress. Not only that Waypoint shows no stats whatsoever for the last mission which is weird; if I go to the mission select it shows the last mission beat on Heroic and I have access to the epilogue movie.
Any ideas? Does it take time to update? This is the first time I checked right after completing a mission.