…but Waypoint says mission 8 (Midnight) is incomplete! I finished it two full days ago. I have both the LoneWolf and the other achievement for completing the campaign on legendary. Why isn’t Waypoint updating? And on top of that, I’m also having the disappearing load outs and SP issue that so many others have reported.
It happens sometimes, and it won’t update by itself. Just play through the mission again on Legendary, and make sure you are connected to Xbox LIVE the entire time. You can even start at the last rally point.