Have Yourself a Morlock Little Christmas - S4-E12
Continuity mistake: Rogue's headband is flesh-colored when Beast says "It would appear that my face is not the world's most reassuring." (00:16:30)
Have Yourself a Morlock Little Christmas - S4-E12
Continuity mistake: When Leech is first shown in his sick bed, he is shirtless and under the sheets. When he begins receiving a blood transfusion from Wolverine, he is fully clothed and also wearing a beanie. Given the weak and near-death state he was in, it's extremely unlikely the other Morlocks would bother dressing him. (00:09:20 - 00:14:15)
Have Yourself a Morlock Little Christmas - S4-E12
Continuity mistake: The brown patch on Ape's left leg disappears when he gets up to assist in Wolverine's blood transfusion for Leech. (00:13:15)
Have Yourself a Morlock Little Christmas - S4-E12
Continuity mistake: When Jubilee is holding Mariana, her right arm goes from cradling Marian's head to being under her bottom. Jubilee also goes from wearing yellow gloves to being bare-handed. (00:11:40)
Have Yourself a Morlock Little Christmas - S4-E12
Continuity mistake: Callisto's eye-patch changes sides when she is berating Storm. (00:09:30)
Have Yourself a Morlock Little Christmas - S4-E12
Continuity mistake: Jubilee's presents suddenly become smaller when she, Storm and Wolverine depart for the Morlock tunnels. (00:08:45)
Have Yourself a Morlock Little Christmas - S4-E12
Continuity mistake: The boxes and ribbons in the stack of gifts that Jubilee is carrying change color. (00:05:20)
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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