I used to go a lot to a particular restaurant which I really liked which I remember had a bad review about a rude waiter. The review described that waiter in detail, and despite going there all the time I never saw him there. The review said that waiter was really rude, but I've never seen anyone be rude there. The staff was always quiet, professional, and polite. I couldn't imagine any of them being rude to anyone. Maybe that waiter had once worked there, but got fired or quit and was no longer there, but the review remained.
After some years the restaurant closed for renovation, and when it reopened there were completely different people working there, and the food was way worse. It was probably sold or went under new management, though they kept the name. So all the reviews this place had gotten over the years were really no longer relevant, as it was effectively a new restaurant. Yet all the Yelp reviews remained.