Yesterday, I started the Master Chief Saga playlist and finished Halo CE. I saved and quit at the start of The Armory level in Halo 2. When I went to resume my progress today, the game started loading up the Halo level from Halo CE, even though it was supposed to resume from The Armory. It says that I have 11/45 levels completed in the playlist, so the game recognizes that I completed those levels. Then why is it loading Halo instead of The Armory? There’s no way I’m going to restart the entire playlist and lose all my progress, especially if this is just going to happen again.
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> Yesterday, I started the Master Chief Saga playlist and finished Halo CE. I saved and quit at the start of The Armory level in Halo 2. When I went to resume my progress today, the game started loading up the Halo level from Halo CE, even though it was supposed to resume from The Armory. It says that I have 11/45 levels completed in the playlist, so the game recognizes that I completed those levels. Then why is it loading Halo instead of The Armory? There’s no way I’m going to restart the entire playlist and lose all my progress, especially if this is just going to happen again.
The same thing happened to me, too! I think it might have something to do with hitting Restart Level or Last Checkpoint. If you want to be extra sure that your progress is recording, just Save/Quit after every level or two. That’s what I did, and it ended up working for me. 
Yeah won’t work for me either. On my second playthrough with the same problem happening again. I have no idea what to do.