I should point out that when I finally did the 5th attempt, I had no instanced team with me and completed the mission in about 2 minutes just fine all by myself.
Whatever is going wrong with missions tonight is centered on joining open instance teams. I don't know which team members are or are not getting credit for mission completion. I only know that ALL my instances tonight in which I had teammates for the last couple hours have ended in me not getting credit.
I did get credit for two patrols before the Beytan V mission, during which I had several teammates. I have no clue what broke.
For the people who are saying the mission does not complete - Did you answer all the questions properly? and if so did you contact Admiral Quinn once you return to sector space to turn in the mission?
What I found is that this happens if ALL THE MEMBERS of a TEAM.. DO NOT LISTEN TO ALL THE COMPLAINTS, (which happens if some of them lag, or split off to get anomalies), even if all the answers are given correctly. On character, tried 3 times to team complete the mission before I got fed up, quit the team, and did it solo...
I've found a solution for this problem.
When you enter the Beytan system, you may have the vulcan sector patrol quest and you get a "new" quest to patrol the beytan system. just drop the patrol quest and the mission should be completeable. after the mission is compelte accept the "vulcan patrol"-quest and trust your eyes
that worked for me with no group (To the person I kicked of my team, I'm sorry, but I finally wanted to end the quest)