Formula 407 - S1-E12
Revealing mistake: After Major Keller leaves in the car with Steve and the formula, when Wonder Woman rushes in front of Maria to protect her when she's being shot at, the wired remote that controls her bracelet sparks is visible in her left hand, as she moves her arms to deflect the bullets.
Answer: The transformation twirling was invented for the 1970s TV series only, to explain her quick change from Diana Prince to Wonder Woman. However, it would have been nice to do a little spin homage in the movie.