Other mistake: When Magneto is asking how the Savage Land mutates were able to infiltrate his citadel, Amphibious tells him it's because Mr. Sinister long ago found his secret passage. The room they are in leads to a balcony, and has no door sealing off the balcony. In a world of superpowered beings, some of whom can fly, it wouldn't take much effort to get into a building that isn't closed off. Finding a secret passage from the ground level would be unnecessary. (00:15:00)
Continuity mistake: When Morph is laughing at Wolverine, the colors on the X emblem on his waistband have been inverted. (00:12:51)
Continuity mistake: When Morph, Jean, and Cyclops are all knocked unconscious by Ruckus' scream, Morph falls to his right, and Jean and Cyclops fall forward. A couple of shots later when their bodies are shown on the ground, Morph is suddenly between Jean and Cyclops, despite falling the opposite direction of them. (00:11:30)
Factual error: When Morph, in the guise of Mr. Hyde, is asking the X-Men who they are, the hair on his reflection in the mirror is parted in the same direction as the real person. (00:06:32)
Continuity mistake: When Jean plays the message from Morph, the analog meters below the player are white. When the shot changes, they are brown. (00:05:09)
Continuity mistake: When the lone sky-rider is flying towards Magneto, Magneto is grasping the cliff with his right arm. When the shot changes, Magneto is suddenly swinging from a tree branch growing out of the cliff in order to kick the rider off his pterodactyl. (00:03:22)
Mojovision - S2-E11
Continuity mistake: When Wolverine is climbing the building, his upper body is shown as being higher than the top story windows. When he calls out to Jean after she gets attacked by the Punisher robot, he is now three floors down. (00:16:03)
Mojovision - S2-E11
Continuity mistake: After Rogue and Beast have been shuffled out of the cube and into their television program, Jean is shown sitting down and leaning back on her elbows, while Wolverine is on his knees. When the shot changes, both are now standing upright. (00:13:08)
Mojovision - S2-E11
Continuity mistake: The cube that Mojo has the X-Men captive inside is transparent on all sides, except for when Cyclops is saying "The X-Men don't fight without a reason." In this shot and the following one, the wall behind them, as well as the ceiling, are now paneled. (00:09:36)
Mojovision - S2-E11
Continuity mistake: When Mojo first starts talking to Cyclops through the television screen, Jean is standing next to Cyclops on his right. She then disappears and reappears for the next several shots, and when Mojo is telling Cyclops that he's offering the X-Men a lifetime television contract, she walks up to Cyclops. (00:04:59 - 00:05:48)
Mojovision - S2-E11
Continuity mistake: When Mojo is talking to Cyclops through the television screen, the screen is roughly the size of a car's back-seat window. When the shot changes, the screen is drastically larger. (00:05:02)
Mojovision - S2-E11
Factual error: When the title screen for Longshot's television show is reflected in Mojo's right eye, the reflection is not reversed like it should be. (00:02:00)
Continuity mistake: When Carly is telling Graydon Creed to leave her alone, her head is tilted towards her right shoulder. When the shot changes, she is facing straight. (00:15:57)
Continuity mistake: When Cyclops says to Beast "We're ready to help," his left hand comes into view, and you can see it is bare. Moments later, he is now wearing a glove on that hand. (00:14:55)
Audio problem: When Jean Grey exclaims "No!" after Ms. Marvel says "This ends now," she is speaking in Ms. Marvel's voice. (00:18:59)
Continuity mistake: When Rogue and Ms. Marvel crash-land into the ground, Rogue pushes Ms. Marvel to the side, with Ms. Marvel's hair being near the edges of the hole in the ground. When the shot changes, the edges of the hole are still in shot, but Ms. Marvel's hair is nowhere to be seen. (00:15:31)
Continuity mistake: When Rogue walks by Carol Danvers' hospital room, you can see a nurse in the open space between the open door and the door frame. When the shot changes, the nurse is now standing in front of the open space, and would have been at least partially obscured by the door in the previous shot if she was standing in the same place. (00:10:11)
Time Fugitives: Part 2 - S2-E8
Continuity mistake: When Cyclops is saying "Don't worry, we'll stop them," the communication device on his bandolier is colored yellow, when it should be red. (00:16:27)
Time Fugitives: Part 2 - S2-E8
Continuity mistake: When Bishop is saying "It's time I lost that guy, once and for all," his mustache is suddenly thicker than previously shown. (00:07:56)
Time Fugitives: Part 1 - S2-E7
Continuity mistake: When Beast is saying "A viral weapon could be easily concealed," his right hand is raised, and you can see that his thumbnail isn't long. When he begins pressing buttons on the control panel a couple of shots later, his right thumbnail is now long. (00:16:34)
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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