I certainly hope this is known, but if you put anything on Auto-Explore, even if they're two different ships in two different parts of the galaxy, on two different turns, they'll eventually smash together and begin exploring the same areas together. One ship will move all the way over to get to where the other one is, and they'll just start following the same auto-explore waypoints.
Quite easy to duplicate. Just build some scouts and put them in auto-explore. It works nothing like it used to, like it was supposed to.