Continuity mistake: When Wolverine and Cyclops are first shown sitting in the courtroom gallery, the wall behind them is bare. When the shot changes, a door has appeared behind them. (00:08:25)
Continuity mistake: When Magneto destroys the wall of Beast's prison cell, the night sky is visible. When Magneto is asking Beast why he isn't escaping, another wall is now there instead of the sky. (00:03:21 - 00:04:06)
Continuity mistake: When Sabertooth is attacking the courtroom, he knocks out three guards with a chair. A couple of shots later, only one guard is on the ground, and when the shot changes again, none of the guards are on the ground anymore. (00:11:15)
Continuity mistake: When the people begin throwing tomatoes at Beast, the judge in the background is sitting down. When the shot changes, he is standing. (00:10:04)
Continuity mistake: When Magneto drops Wolverine, Storm and Cyclops onto the ground, Wolverine and Cyclops are lying mostly perpendicular to Storm. When it changes to a shot of them getting up, they are all parallel to each other. (00:17:18)
Continuity mistake: The prosecutor for Beast's trial is wearing a pink suit. When the unruly civilian is being escorted out of the courtroom, in a wide shot, the prosecutor's suit is now white. (00:08:29 - 00:10:22)
Continuity mistake: When Xavier is using Cerebro to look for Magneto, his blue and black tie turns yellow when Jubilee says "Professor?" When Storm says "Charles, are you all right?", it is back to being blue and black, and the blue stripes turn yellow before our eyes. (00:11:41)
Continuity mistake: When Storm is free-falling after stopping the missiles, the communication device on her left side is flashing as Cyclops is speaking to her, and as her body rotates, it becomes the right side device that flashes. (00:19:53)
Other mistake: When Cyclops is turning on his communication device to talk to Storm, his fingernails have been drawn on his gloved hands. (00:18:50)
Continuity mistake: When Storm shoots lightning at the missiles, it is yellow. When the shot changes, it is blue. (00:19:40)
Continuity mistake: When the bailiffs are escorting the unruly civilian out of the courtroom, the members of the gallery behind the prosecutor are different and fewer in numbers than they were earlier in the scene when the prosecutor was making her case against Beast. (00:08:29 - 00:10:22)
Continuity mistake: The stains from the tomatoes that are thrown at Beast disappear from his jumpsuit. (00:10:05 - 00:10:55)
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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