The Phalanx Covenant: Part 1 - S5-E1
Continuity mistake: When Sabretooth is terrorizing the police and civilians, it is broad daylight outside. When Beast and Jubilee are shown approaching the scene in the Blackbird just before dispersing tranquilizing gas, it is twilight. (00:01:00 - 00:01:50)
The Phalanx Covenant: Part 1 - S5-E1
Continuity mistake: When Jubilee accidentally lets slip that Sabretooth is in the mansion in front of Wolverine, the hand portions of her gloves disappear. (00:03:00)
The Phalanx Covenant: Part 1 - S5-E1
Continuity mistake: When Wolverine confronts Sabretooth in his holding cell, Wolverine's face is colored yellow. (00:04:25)
The Phalanx Covenant: Part 1 - S5-E1
Continuity mistake: When Wolverine lunges at Sabretooth, his normally-red belt is colored yellow. (00:04:55)
The Phalanx Covenant: Part 1 - S5-E1
Continuity mistake: When Beast is running from the Phalanx through the mansion's hallways, his trunks go from being Speedo-like to resembling basketball shorts. (00:06:50)
The Phalanx Covenant: Part 1 - S5-E1
Continuity mistake: When Beast is trying to escape the Phalanx in Wolverine's jeep, he has to drive down a considerably long road just to reach the gates to the mansion. In all previous episodes, the road leading to the mansion is barely longer than a driveway. (00:08:35 - 00:09:10)
The Phalanx Covenant: Part 1 - S5-E1
Continuity mistake: When Beast replays the video of Warlock's tissue sample assimilating the metal, the human and mutant tissue samples on the left have disappeared. (00:11:35 - 00:12:30)
The Phalanx Covenant: Part 1 - S5-E1
Continuity mistake: When Beast says "And we waited until you arrived," his eyebrows keep changing from blue to black. (00:16:10)
The Phalanx Covenant: Part 1 - S5-E1
Continuity mistake: When Mr. Sinister blasts the Phalanx-civilians, his gloves are red. A couple of shots later, his gloves are their usual blue. (00:17:50)
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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