I don't think this has ever gotten any official clarification; even when this was brought up during the Playtest.
The way I've most commonly seen it ruled, though, is that you do not need to recover or re-manifest the swarm strike. The rationale is that your nanites are, overall, still on your person: they're still the Sheathe array. The Sheathe array hasn't left you, it doesn't end its turn more than 10 ft away from you, etc. Your fancy swarm strike Sheathe array just lets you punt a small glob of nanites far away.