Homeworld 2, Mission 11 - Bentusi Ruins
I had already destroyed the Shipyard and Vaygr Carriers before I collected the parts of the Bentusi Core. After I get the 3rd part I'm told to destroy all remaining Vaygr forces. Problem is there aren't any. I used a sensor ping and nothing turned up. I think they retreated off the edges of the map where I can't get to them. My own interceptors have wandered off a few times as well.