If I have a ship in sector sweep, then take it out of sector sweep, send it to another sector, and place it back in sector sweep mode, it lays out a course to the original sector it swept and doesn't stay in the new sector.
Stardock Forums
I've seen the 99 pre-cursor corvettes, also. I wondered what they would do with them, so I focused on them at the end of my turn and started watching them dash the corvettes to pieces against the dreadnaughts of whichever race they were fighting--they even managed to destroy one already wounded dreadnaught. The next time the event occured, I wandered away from the PC while the AI deployed their corvettes. I was excited when I finally received the pre-cursor find in my last gam