I grinded so long last night to get all 15 co-op levels and all 3 campaigns playlists including the one for halo 3 and I didn’t get any rank tokens or XP. And when I got on today all my challenges reset all the way back down to zero. There are a lot of other people dealing with this same problem on YouTube and reddit. It seems to just be an Xbox issue. I’m sure 343 will make a fix in coming weeks but I am going to be very frustrated if I have to spent another 5 hours grinding out the challenges. I took a picture of them before I turned my Xbox off for the night cause I knew they were going to reset.