One of my forward fleets has been locked in "a space battle in progress" in a system that has an orbitting Vodyani hero. There was a Vodyani fleet there consisting of that lone hero and one other ship, which my fleet engaged to protect the system. But that was about 12 turns ago, and I haven't been able to move my fleet from that system since.

Also, those weird, empty grey pirate hangars are there. I can't get rid of them by building my own ships in that system either. Help!