>>46148911All the early movie trailers featured examples of this.
The second movie's original trailer features a crazy final shot, it seems like things were originally going to go off the wall after the Legendary Birds were captured:
https://www.youtube.com/watch?v=NAbopqlZ_0cAnd in Pokemon 3's trailer, the return of Mewtwo is teased:
https://youtu.be/yNm4tyl9hVAThis wasn't unique to Pokemon films either, it was common for anime movie trailers to feature scenes and story elements that did not make it to the finished product. Because their turnaround is so fast, they were actually producing trailers based on non-finalized scripts, and animating cool scenes that might happen just for the trailer.