Dawson Casting: Tessa, who is 17 during the film's events, was born when Cade was a teenager, meaning Cade is at most in his mid thirties. Mark Wahlberg was 42 during filming.
Lying Creator: Bay said that the film was going to be the shortest of the series, with reports of a 120 minute running time floating about. Turns out those reports are false and the running time that has been revealed is 165 minutes, making it the longest of the series so far.
No Export for You: The tie-in toy line. With most of the "regular" toys being sold under the Generations series, which only gets a wide release in a select few countries, this is the first movie-based TF toy line that (aside from the simplified, gimmicky figures aimed at small kids) doesn't even see a first-wave release in a lot of places of the world.
Stringer was going to be a fembot named Widow Maker
Dwayne Johnson was originally offered the role of Cade.
Optimus was supposed to have an armor-up scene where he added new weapons to his robot mode. This would have explained why he suddenly gained flight at the end of the movie.
According to Transformers Manager of Global Brand Development Mark Weber at New York Toy Fair 2014, Strafe is named so not because of trademark reasons, but because the film's two-headed design was considered too great a departure from previous Swoop characters.