A lot extra.
Have done all the requirements had one left on 97% complete did the last bonus objective didn't pop did it again didn't pop one more time for good luck in co op even still didn't pop.
Really annoyed at this cos it keeps appearing in my closest to completion list and I've done it.
I have been in the exact same boat (a lot extra, 97%) for three years. There’s a very good chance that the one you need isn’t the one you think. There are three different ways to track it: what the game says, what xbox says, and what Waypoint says. And they can all say different things. It’s very frustrating. I even once got in contact with some 343 personnel who looked into the backend for me. They recommended redoing specific missions, but after a couple of their suggestions didn’t work, communication just stopped.
Try deleting all game data, reinstalling, and see what objectives it says you’re missing. That might shake loose what you’re really missing (but do some research on the process first, don’t take my word for it). And if that doesn’t help, beyond redoing every mission individually and getting every single objective during each uninterrupted playthrough, there’s little that can be done.
I try to get it about once a year, but I fear this bug has been ignored and won’t be ever fixed. Pretty -Yoinking!- disappointing, as it’s been around since launch. Even with all the refreshes and focuses over the past couple years, they never addressed this one.