I beat all of the Spartan Ops missions from all of the Episodes/Chapters and did not get my gamerscore or achievement. Is there anyone else experiencing this issue?
Yes it’s happened to just about everyone. You just need to go back and replay a mission solo and it should unlock.
I played the first chapter of this episode on easy and it unlocked.
I got disconnected but it still unlocked for me after a Solo mission
So I think its something like the campaign where sometimes it just doesnt register.