Assuming that there's no branching histories here, this means that there are two Nue; the one that just joined the crew and the one that's infinitely old and doesn't exist outside of that time loop of being sealed, being released, and traveling back in time again.
Of course That's assuming that the Nue who was sealed actually left instead of just disappearing when they brought (started to bring) past Nue to the future.
That'd require branching histories, though; if she didn't leave, then there'd be no Nue in the past to get sealed, and then no Nue in the (relative) present to be freed along with the ship.
The Nue from the future made a break for it back at post #1386158.
Yeeeeeeaaaah!!Now, let's go home. To the future!Wasn't she supposed to be hiding!?She's gone!What about the current Nue!?Ah!Now that you mention it, where is she!?You're going to the future, right? That seems fun! I'll go too!Oh crap! The Nue from the past is still here!