Reshooting scenes from a movie isn’t an uncommon practice, and it’s especially not uncommon in comedy and action films. Actors and directors spend days and weeks and months putting written word into observable action. Long days can lead to oversights (see: Starbucks; Game of Thrones) that may or may not (see: previous parenthetical) be caught during post-production and editing that requires scenes to be reshot.
Or, in the case of X-Men: Dark Phoenix, another movie simply snaked the ending.
According to actors James McAvoy and Michael Fassbender, the ending to Dark Phoenix was completely revamped because of another superhero movie stole its thunder. The specific movie isn’t revealed, but some speculate that Captain Marvel is the culprit. McAvoy explains in an interview with Yahoo UK: “The end changed a hell of a lot. The finale had to change. There was a lot of overlap and parallels with another superhero movie that came out… a while ago.” Fassbender went on to joke that “they had spies on set.”
Dark Phoenix was already pushed back from its November 2018 date to February of this year, only to get delayed once again. It’s now set to release, once and for all, on June 7th.