In my latest playthrough, I've caught the very first outsider I came across, and was very surprised to encounter an additional outsider a while later on a different crashed UFO (as I was under the impression they stop showing up once you fulfill the objective of capturing one).
I really wanted to see what would happen if I were to capture it, but I obviously failed (which is why I'm asking this question).
I seem to recall that the outsider shard shows up on the gray market screen and is unsellable. Will capturing an additional outsider give me an extra shard to sell once I research the one I already had? Will I simply end up with an extra shard I can't do anything with? Something else?