In Scooby-Doo! Pirates Ahoy, there's a glaring error with an assertion that Velma makes. When the hologram of the U.S.S. Cyclops goes by, Velma exclaims that it is impossible because the ship has been sunk for over one hundred years. At the time of the film's release, this was incorrect. In real life, the U.S.S. Cyclops was sunk in March 1918. It was assumed to be either lost at sea or sunk by the Imperial German Navy.
Thanks Mr. Neither for coming up with this week's fun fact!