The Phalanx Covenant: Part 2 - S5-E2
Continuity mistake: When the group is standing together in a circle at the end, Xavier is sort of in the center of the circle and Rogue and Storm are several feet to his right. When the shot changes, Rogue and Storm are suddenly right next to Xavier. (00:19:25)
The Phalanx Covenant: Part 2 - S5-E2
Continuity mistake: When Beast says to Warlock "We are at your disposal," Magneto is suddenly clean-shaven. (00:16:35)
The Phalanx Covenant: Part 2 - S5-E2
Revealing mistake: When Forge says "That's where we'll begin our assault," his mustache disappears from his face. (00:14:50)
The Phalanx Covenant: Part 2 - S5-E2
Continuity mistake: When Cameron Hodge is duplicating Gambit's mutant power, his arm is yellow. When the shot changes, his arm (or at least his hand) is flesh-colored. (00:13:35)
The Phalanx Covenant: Part 2 - S5-E2
Continuity mistake: The Phalanx-infected Gambit goes from being yellow and black in one shot to having the appearance of his usual color scheme in the very next shot. (00:13:30)
The Phalanx Covenant: Part 2 - S5-E2
Continuity mistake: When the group is talking to Cameron Hodge's Phalanx facsimile, sometimes Forge is behind Beast on his left, Mr. Sinister is behind Forge on his left, and Warlock is behind Forge and Mr. Sinister. Other times Warlock is behind Beast on his left and Forge and Mr. Sinister are not in the shot. (00:10:45 - 00:12:45)
The Phalanx Covenant: Part 2 - S5-E2
Continuity mistake: When Magneto says "To do what?" he is wearing his purple gloves. When he is shown in closeup, he is not wearing any gloves, just a red long-sleeve shirt. (00:08:35)
The Phalanx Covenant: Part 2 - S5-E2
Continuity mistake: After the Phalanx captures Banshee, the bubble he is encased in disappears when the shot changes. He also goes from being turned away from Moira to facing her direction. (00:07:40)
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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