I ran into this last night, but I had a CTD right as it blew up. I dropped the mission and ran it again and once I was back in sector space I was able to turn it in, but I could not while in the instance still.
I've now done this mission twice. Another bug in the same mission (last night and tonight) is that if you die, you cant respawn. You have to exit sector to respawn. I also completed it AGAIN and can't turn it in. Help?