Spoilers ahead
  1. In The Hobbit : Desolation of Smaug, Smaug does not get desolated. He lives on until the next movie.
  2. Last Man on Earth is also incorrectly titled.
  3. Static
  4. The fact that Cho Chang is in the room of requirement in Deathly Hallows part 2 in her school uniform when she graduated Hogwarts the year previous