The Bermuda Triangle Crisis - S2-E4
Revealing mistake: When Wonder Woman drops a mine into the water, she's supposed to be dropping it into the ocean. However, you can see a drain plug of some sort in the background and the "ocean" is obviously a pool, or similar.
The Bermuda Triangle Crisis - S2-E4
Continuity mistake: Steve and Diana steal wrinkled uniforms from a clothesline. However when they put the uniforms on, they're perfectly pressed.
The Bermuda Triangle Crisis - S2-E4
Continuity mistake: After Wonder Woman gets Steve out of the tree, you can see a big shrub in the foreground on the right side of Steve's body. When the camera changes angles, the shrub is suddenly gone.
The Bermuda Triangle Crisis - S2-E4
Continuity mistake: Steve's parachute moves around, even though it's flat on the ground and no one moved it. After Wonder Woman rescues Steve from the tree, Steve is laying on the ground motionless and unconscious. His parachute moves around between the time Wonder Woman walks away and Diana returns, even though nothing could have moved it. It wouldn't be so obvious, except that the material is red and white, so when it changes, you can really tell.
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.