In the first edition of Harry Potter and the Chamber of Secrets, there is a passage:
"You can speak Parseltongue, Harry," said Dumbledore calmly, "because Lord Voldemort - who is the last remaining ancestor of Salazar Slytherin - can speak Parseltongue."
Here, there is an obvious mistake as Voldemort is the last remaining descendant of Salazar Slytherin. This error is fixed in a later edition. On which edition is this fix first applied?