If you’ve seen “Logan,” you may have spotted a significant continuity error.

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Caliban, the mutant who made his firstappearance in “X-Men: Apocalypse,” was also seen in “Logan,” albeit with a new actor (Stephen Merchant played Caliban in “Logan,” whereas Tómas Lemarquis played the character in "Apocalypse"). In addition, the character boasted a new accent, and completely different personality. How did that happen?

It turn out that “Logan” director James Mangold realized the continuity error too late.

Tómas Lemarquis as Caliban in X-Men: Apocalypse
Tómas Lemarquis as Caliban in X-Men: Apocalypse

“It’s a funny, messy story of how so often these things are not as coordinated as everyone thinks,” he told CinemaBlend. “I actually had written him into our movie, and they didn’t know [he was] in 'Apocalypse,' and then they kind of wrote it in their movie, and they cast someone in their movie and I had not seen it and was working away on mine.”

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Even with the realization, Mangold ultimately decided to change nothing to keep the integrity of his story. He said that instead of finding a different character to fill the Caliban spot, he kept his script as it was because he liked the “particular energy that we wrote.”

At the end of the day, it’s not the biggest of deals, since “Logan” still succeeded. But it’s still another thing for continuity sticklers to keep in the forefront of their minds when it comes to analyzing how consistent a franchise is with their characters and storylines.

In theaters now, "Logan" stars Hugh Jackman, Patrick Stewart, Boyd Holbrook, Richard E. Grant, Dafne Keen and Stephen Merchant.