I've run this twice (very hard to get groups on tribble)
The first time seemed fine.
The second time the mission bugged and wouldn't complete. 2 things could have caused it
The game hung up at the end of phase 3, where you protect building from damage.
1. The industrial sector failed completely. I would think this be accounted for but who knows.
2. At the end of the time, Residential building 2 was very low in health. The health bar of all the other buildings disappeared but this one didn't, there was also a romulan standing outside the building.
Could the romulan bug it? Was it a beta that pulled a romulan out and it didn't get back in before the time? It wasn't my sector so I'm not sure what was happening.