In Goblet of Fire, when Molly and Billy Weasley come to visit Harry before the Third Task, Molly talks about Hagrid’s predecessor.
Mrs. Weasley was intrigued by the Whomping Willow, which had been planted after she had left school, and reminisced at length about the gamekeeper before Hagrid, a man called Ogg.
— Goblet of Fire, chapter 31 (The Third Task)
But wouldn’t Hagrid have been gamekeeper when she was in school?
Hagrid was kicked out at 13 around 1943 and began training as gamekeeper. Molly would have arrived at Hogwarts in the early 60s when Hagrid would have been 30. Even if he was still in training or assistant gamekeeper, he would definitely still be there with Ogg. And as Ogg is described as the gamekeeper before Hagrid, that seems to imply that they weren't there together in Molly's memory. How does that work?