Halo2 LASO campaign achievement not unlocking

Games Halo: The Master Chief Collection
1

Hello,

I’m writing this ticket because I have been playing and completing the halo2 LASO campaign with my friend “Plaffy46”, the issue being he got the achievement and I did not even though we played from start to end together. Is there any way to fix this?

Thanks for your attention.

Sincerely,

Cos3tte