What's the backstory on the Jeopardy contestant who reappeared Dec 31?

What’s the backstory on the Jeopardy contestant who reappeared Dec 31?

I missed the explanation. Can you explain it o provide a link?

According to Jeopardy Archive here it was the way the clue was phrased in Final Jeopardy.

The category was Famous Last Names

The correct response was “Collins”. Michael Collins was on the Apollo 11 mission that landed on the moon, but he stayed in the command module in orbit around the moon and did not take part in the actual landing.

There was also a show a couple weeks ago in which the returning champion did not appear. It was a Monday show, so I assume something happened between shooting one batch of shows and the next. Anyone know the details behind that, or what was said on the show to explain it?

I didn’t catch the details, but it was for personal reasons: called in to work, family emergency, prior obligations, something like that.

Claudia Corriere won two games in a row, but did not return to defend on the next episode. Alex Trebek’s knee surgery and recovery caused an unexpectedly long delay between the taping of her second show and what would have been her third. In the meantime, Claudia (a professional musician) had accepted a gig that interfered with appearing at the next taping. Alex said she would return as a Jeopardy! contestant early in 2016, presumably alongside whoever is the reigning champion at that time.

Well, glad to hear that she’ll be back. It would suck to finally get on the show, and even win, and have to drop out over scheduling.

JArchive says that was the second time this has happened. I wonder when the first was.