Halo Reach LASO Playlist Achievement Not Unlocking

I’ve seen numerous threads about achievement issues with this game, so I thought I’d throw mine in there.

I completed the Halo: Reach LASO playlist, on Xbox One X, solo, all missions in order, and didn’t get the achievement. It says 12/12, and nothing. I know there are issues with doing it in co-op and completing missions out of order, but I never played co-op, not even once.

I also know a possible workaround is to have someone give you a checkpoint at the Epilogue and finish Lone Wolf again. Anyone with a checkpoint to share that I could borrow to test this? My Gamertag is: bblcreator8790

I completed the Reach LASO playlist from Winter Contingency to Lone Wolf, but I didn’t get the achievement, because the playlist skipped Noble Actual. The game checks if you have the LASO playlist completed 12/12 when you finish Lone Wolf. In my case it was 11/12.

I joined a friend who had done his LASO playlist all the way to Lone Wolf and I joined in on the Lone Wolf mission as co-op. We finished it and I didn’t get the achievement right away, but I got it to pop when I exited the lobby and went into my Reach playlists, where the LASO playlist then read 12/12.