Other mistake: When the two civilians are walking past Joe McTaggert's campaign posters, they are shown to be walking unusually fast, almost as if the ground beneath them is moving them forward between strides (similar to as if you were walking on a moving sidewalk inside an airport). (00:03:00)
Other mistake: Moira's arms are disproportionately long when she rescues Xavier from falling into the pit. (00:12:30)
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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