I have been playing a few times Second Wave mission, and through my first playthrough, I selected the Jem'Hadar Polaron Beam Pistol as reward. In one of my other playthrough, I tried selecting the Jem'Hadar Polaron Full Auto Rifle.
The error came up saying, you already own an unique item... I assume it was referring to the Beam Pistol I received earlier. So. I discarded the Beam pistol and relogged... Since trying to accept the Rifle then, didnt work either. But even after relogging, it keeps saying that I still own an unique item. And I can only have one of them.
But I dont have the beam pistol anymore :/ However I could accept the Beam pistol again, but not the Rifle :s
Retried another, and then ending was bugged... mission never was succesful... even as it was... *sigh*
I'll try another time tommorow, but its does seems a bit bugged somewhere