Clemont & Xerneas
The Diancie movie, much to the disappointment of some fans, spoiled the evolution of Ash’s Fletchling by incorporating Fletchinder a week prior to the evolution taking place on TV screens. The temptation is to solve this by simply pushing the movie and it’s related specials back a week to solve the continuity issues and ensure that future viewers will not be spoilered in the same way.
However in a slightly later episode Xerneas appears and goes unrecognised by all but Clemont, who seems ready to name that Pokémon just before being interupted by Tierno.
Astounding! Is that–
– a pokémon? Amazing!
This also fits with Clemont’s familiarity with the legend of Xerneas portrayed in the film. Since there’s no roster changes and no real change in geography (still being on Route 11) it seems acceptable to push the movie back until the close of the Pokémon Summer Camp arc, just before Ash’s arrival at Shalour City.
Source: GameFAQs Pokémon Message Board