MCC Halo 2 Lvl 15 Legendary not showing completed

Apologies for posting in the general forum (found other people with the same problem) and this one … just noticed the specific support forum

Finally finished MCC Halo 2 level 15 on Legendary after defeating Tartarus - went through the video clips at the end then it said player not logged in and bounced me back to the main menu.

Had a look at the missions now and it doesn’t even show that Level 15 has been started let alone completed. There were even a number of saves along the way as I progressively worked my way through the level.

Last thing I want to do is to run through it again and still not have it happen.

Would be good if 343 could check, update for the Gamertag and also fix the problem.