Cross posted from r/prancingponypod . A user there suggested that Hammond & Scull might be interested in this, or have documented it:

I came across a typo in the Ballantine paperback version of FotR around 1980. In "The Mirror of Galadriel," after Frodo recites a poem he had composed in memory of Gandalf, Sam exclaims to him,

"Why, you'll be beating Mr. Bilbo next!" said Sam.

"No, I am afraid not," said Bilbo. "But that is the best I can do yet."

I thought it was hilarious to visualize Bilbo suddenly teleporting from Rivendell to Lothlorien to reply indignantly to Sam that Frodo could never rival him at composing poetry (maybe via a palantir wired into Galadriel's Mirror?).

I mentioned this during a D&D session I was having with my college buddies at the time. They excitedly ran to our host's bookshelf to get his copy of FotR, which was an earlier printing maybe from a different publisher. Sadly, that printing correctly had Frodo, and half of my buddies thought I'd just imagined it. I lost track of that set of books except for The Hobbit (17th printing, May 1978), and have never encountered that typo in any other edition.