Audio problem: When Mr. Guthrie is saying "I worked with you inside the mines and shopped in your stores," his mouth is completely out of sync with the dialogue, sometimes not even moving at all. (00:14:45)
Other mistake: When Rogue rendezvous with Beast, Xavier and Gambit, she pinches Gambit's cheek with her bare fingers. This should have caused her to drain his powers and render him unconscious. (00:14:10)
Continuity mistake: In one shot before the nurse shaves a patch out of Gambit's hair, the neck portion of his black headgear is flesh-colored. (00:12:40)
Continuity mistake: The ice cream that Cannonball drops when Kenny confronts him disappears in subsequent shots. (00:10:50)
Continuity mistake: Kenny's hair goes from being light-brown to blonde. (00:05:50 - 00:11:00)
Continuity mistake: When Gambit is restrained in the chair, his gloves alternate between being his usual gloves that are fingerless at the thumb, index and pinkie fingers, to not being fingerless, to him not wearing any gloves at all depending on the shot. (00:10:05)
Continuity mistake: When Gambit jumps out of the ventilation shaft, there is no one around him. Then he is suddenly surrounded by guards who could not have converged on him so quickly unless they appeared out of thin air. (00:10:00)
Other mistake: When Gambit pushes out the vent shaft cover from inside the ventilation system, his hands emerge gripping the outside of the cover. This would be physically impossible. (00:09:55)
Continuity mistake: Gambit uses his staff to pole vault himself across the rooftops. When he lands, the staff has vanished. (00:09:30)
Continuity mistake: When Kirkland is going through photos of Rogue, he stops on a photo of the full X-Men team. When the shot changes, the photo he is stopped at is of Rogue and Cannonball. (00:08:25)
Character mistake: When Beast is showing Gambit and Rogue the news report about Cannonball, it is shown to be featured in a magazine called Philologist's Quarterly. When Beast leaves the room, he remarks "Ah, there's my 'Philologist's Quarterly'." as if he didn't already see it. (00:04:25)
Continuity mistake: When Rogue and Gambit are playing pool, Rogue's arms are bare from the elbow down except a yellow wristband on each wrist. When Beast comes in with the mail, Rogue is wearing her usual green sleeves and yellow gloves. (00:04:00 - 00:05:10)
Answer: Chris Potter, the original Gambit voice actor, did indeed quit the role in the 4th season. His last episode was The Phalanx Covenant Part 1 so it seems reasonable that Fox would limit the use of the character even though it was recast. It doesn't appear that Potter left the role due to animosity, he stated in an interview that he wished to play Gambit in the first live action X-Men film.
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