Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Mystique first enters the room where she plans to murder Senator Kelly, there are two bookshelves on the left, with the one closest to the camera being shorter than the one next to it. When Gambit and Mystique are getting ready to square off, the bookshelves are in the background, and they have swapped places. (00:15:52 - 00:16:15)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Mystique is leading Senator Kelly into the room to kill him, a window has appeared on the door after they enter. (00:15:40)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Mystique, disguised as Gambit, is removing the blindfold from the woman, the lines on Gambit's collar armor change length and then disappear. The lines defining Gambit's pectoral and abdominal muscles disappear as well. (00:15:55)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Wolverine has his hands draped around Blob's eyes and neck, the parts of his mask that are next to his cheeks are colored yellow, when they should be black. (00:13:33)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Wolverine is running towards Blob from behind, he is in his direct path. When the shot changes to Wolverine jumping onto him, he emerges from the right side of the screen instead of from directly behind him. (00:13:29)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Blob first confronts the X-Men, there is a light post behind him. When Rogue has her hand stuck in his chest, the light post has disappeared. (00:12:17)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Avalanche and Pyro are attacking the chambers, Avalanche destroys a bookshelf that wasn't there at the beginning of the scene. (00:10:42 - 00:11:17)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Gambit hands Bishop the deck of cards to cut, Bishop places them at a diagonal angle in front of him. When the shot changes, the deck is now pointing straight. (00:09:36)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Mystique is warning the Brotherhood not to fail, the TV is off. When the shot changes, it is suddenly on, and the antenna is suddenly smaller. (00:09:16)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Blob is looking out the hotel window, the window panes have been opened at a 90° angle. When the shot changes, the opened panes are no longer visible. When the shot changes again, the windows are slid open, which would make it impossible for the panes to have been positioned at a 90° angle in the first place. (00:09:07)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Bishop is shooting an energy blast at Gambit, he has three playing cards and five poker chips in front of him, while Wolverine also has three cards. When Wolverine is telling them both to sit down, Bishop now has four cards and eight chips, and Wolverine has four cards as well. Additionally, the deck has moved closer to the center of the table, and the arrangement of Wolverine's chips and the arrangement of Gambit's cards and chips have changed. (00:08:35)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Cyclops is telling Gambit that they can't allow him to leave, he is standing behind Xavier's right shoulder. When the shot changes, Cyclops has disappeared. (00:07:53)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Xavier is speculating if he is the one Gambit is supposed to assassinate, he is at Jubilee's 3 o'clock. When the shot changes, he is now at her 2 o'clock. (00:06:31)
Days of Future Past: Part 2 - S1-E12
Continuity mistake: When Gambit announces his arrival, he is standing just in front of the doorway. When he puts his hands up after Bishop draws his gun on him, there is now a wall behind him. (00:03:07)
Continuity mistake: When Xavier is saying "They can be appealed to, reasoned with," Jean Grey's back is entirely peach-colored, when there should be a blue stripe going down the middle of it. (00:10:36)
Continuity mistake: When Apocalypse is ordering War and Archangel to attack the tanks, Archangel's decollete is the same light blue color as his skin, when it should be the darker shade of blue that his outfit his, since his outfit leaves his face and hands exposed. The photograph Xavier shows Rogue of Archangel later in the episode also depicts the same error. (00:09:30 - 00:11:12)
Days of Future Past: Part 1 - S1-E11
Continuity mistake: When Wolverine first places the time band on his arm, it is on the upper half of his forearm, just above where his glove ends. When he is pulling the gun out of the cabinet, the band has now moved closer to his hand. (00:08:00)
Days of Future Past: Part 1 - S1-E11
Continuity mistake: When Bishop is watching footage of the X-Men on his armband, in the shot of the team running towards the camera, Gambit's collar armor is colored pink, when it should be blue. When the band displays a still image of the team, Wolverine's bare right arm is incorrectly colored yellow. (00:12:06)
Days of Future Past: Part 1 - S1-E11
Continuity mistake: When Beast is straightening the bent bars to his prison cell, the middle of his waistband has changed color from red to yellow. (00:11:37)
Days of Future Past: Part 1 - S1-E11
Continuity mistake: When Beast is telling Gambit that he must see his incarceration through to the end in his own way, he places his left hand on his chest. When the shot changes, his arm is suddenly down at his side. (00:11:19)
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.
BaconIsMyBFF