“3rd-hand story”, from a friend of a friend…uh, huh. Unless I’m missing a heaping bucket of “ironically”, you could have just said “there’s an old urban legend…” instead of passing off an old joke as something true.
I have been duped like this before too! Believe a story that just doesn't ring right when you tell it to somebody else years later. Teaching / communicating corrects a lot of errors.