According to Jeopardy Archive here
it was the way the clue was phrased in Final Jeopardy.
The category was Famous Last Names
The first woman space shuttle pilot shares this surname with a man on the 1st manned lunar landing 26 years earlier
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?