Co-op missions don't get completed for party of 3 players

Was in a party of 3 and for some reason the co-op mission doesn't get counted for completion. Most of the time it's either 1-2 players that finish while the third player doesn't get counted. Only the Line mission seems to be working but everything else is bugged. Eventually one player had to leave and the bug was kinda solved but anytime we had 3 people in the party is when it got buggy and really annoying for most of us. 

I can't say if the bug affects a full party but if anyone has had that happened to them, it be best to see if that could be fixed.