When Brain is reading while in Alvin the first time we see the inside of book there are no words on the page, but moments later we see the page again and there are squiggly lines on it.
When Pinky and the Brain find the Titanic wreck, they see it is intact when, in fact, the ship broke in two. Before the wreck was found in 1985, the break-up had been debated since the ship sank in 1912.