Glitched Hale CE Playlist

Hello There!
My friend and I going for 100% achievements in MCC. One achievement is to beat the LASO playlist, which was REALLY tough. We finished this playlist today, at the end it shows your score for every mission throughout the playlist. For whatever reason the mission “The Library” isn’t registered as completed. My buddy does not have this issue. Also should mention he hosted all the levels and we beat this playlist together. Please help, any advice would be great! Im not about to restart this playlist to do a mission I already beat. If this was legendary sure, but its LASO… it takes hours.