Factual error: When the large Dutch guy tells his story about his life in Holland, there are a several windmills. However, the blades are placed on the wrong side, that way it's not possible for a windmill to turn clockwise, which it does. If the blades were placed correctly, they would still turn to the wrong side, because wooden windmills in The Netherlands are always turning counter-clockwise.
Factual error: There's an exhibit in the Smithsonian Institute that shows Benedict Arnold, William Demont, and Major John Andre labeled as Famous American Traitors. One problem, Andre wasn't a traitor to America as he was a British officer to whom Benedict Arnold arranged to surrender West Point to during the war.
The Alchemy Murder Case File 3 - S1-E8
Factual error: The Latin text on the supposedly old tome (which is written with a modern font) displays an alchemist diagram. It is a reproduction of a famous drawing meant to portray the Philosopher Stone in the Sylva Philosophorum, but whoever copied it does not know Latin, because certain words are misspelled ("Merceralia" instead of "Mercurialia", "Humides" instead of "Humidus"). (00:10:10)
Welcome to Brickleberry - S1-E1
Factual error: Malloy has been missing all day and is starving from not eating. Yet his cheeks are sunk in like he hasn't ate for weeks. Your face doesn't get like that after not eating for a day.
Factual error: The map of the western United States shown during the weather report at the start of the episode shows some states drawn incorrectly. Idaho's entire western border is a straight line, whereas in real life, Oregon has a horn-shaped indentation on its northeastern border that it shares with Idaho. Idaho also looks like a crude staircase, with the southwestern border of Montana going down to central Wyoming, whereas that area in real life is around the northwestern part of Wyoming.
Ruri chan 'Kôkai nisshi' - S1-E5
Factual error: Amongst the weirdos with personalized funeral requests, besides a guy from England with the same residence as Sherlock Holmes, there's a guy who believes to be a vampire, Gyappy. He really believes in his classic Bela Lugosi character to the point of not having his age written down, but his residence is a generic "Poland, Earth", while it should be Romania or Transylvania. (00:07:00)
Factual error: Even though the show is called "Samurai Jack", Jack isn't really a samurai. The correct title for him would be a Ronin as a Ronin loses their master if their master dies or loses favor with their master and also has no home anywhere. Jack has these attributes. He has no master and no home.
Suggested correction: Nor is his name really Jack. "Jack", and thus "Samurai Jack", is just an alias that the prince takes. It's not meant to be his title or rank. Just like Cowboy Jack wasn't actually a cowboy.