Campaign Achievement problem

I have played through the whole campaign on heroic. However there are 3 missions I did not get achievements for. Mission 4 (Infinity), Mission 5 (Reclaimer) and Mission 6 (Shutdown). I also did not get the achievement for beating the campaign (on heroic). For all the missions that it says I beat, It says I beat them on heroic AND alone so theres no way i just joined another lobby and got the mission done on co-op because I beat them solo. Anyone else having similar issues?
btw its super fun

Same issue on missions 4 and 7 on legendary. Replayed 4 and got it. Not so excited about replaying 7 since I just grinded to get it.