Mojovision - S2-E11
Audio problem: When Mojo is saying "Control room, what are you doing up there?", he doesn't press his lips together at the end of the word "room" in order to pronounce the M sound. Instead, he is shown clenching his teeth together. (00:17:19)
Mojovision - S2-E11
Audio problem: When Magneto is saying "the creature attacking the woman," his mouth only moves for the first two words. (00:20:23)
Audio problem: Gambit's bō staff starts making a twirling sound a split second before he starts twirling it. (00:18:40)
The Phoenix Saga (3): Cry of the Banshee - S3-E5
Audio problem: When Lilandra is saying "No, for the sake of the universe, no," her mouth movement is not in sync for some of the dialogue. (00:18:23)
The Phoenix Saga (4): The Starjammers - S3-E6
Audio problem: When Phoenix says "We must movie quickly to safeguard the crystal," she is speaking in Lilandra's voice. (00:06:10)
The Phoenix Saga (4): The Starjammers - S3-E6
Audio problem: When D'Ken is ordering Gladiator to identify himself, he is speaking in a voice that sounds more like Dr. Corbeau from a few episodes earlier than it does D'Ken. (00:09:20)
The Phoenix Saga (5): Child of Light - S3-E7
Audio problem: Storm's mouth is completely closed when she says "The immediate threat to New York City has been averted." (00:12:10)
Savage Land, Strange Heart (1) - S3-E8
Audio problem: When Sauron is saying "Cowards, fools, come back," his mouth isn't moving. (00:02:02)
Savage Land, Strange Heart (1) - S3-E8
Audio problem: When Sauron says "Ka-Zar, I warned you!", Ka-Zar is actually the one mouthing the line. Note: this mistake may only apply to the DVD version of the episode. Sauron is the one mouthing the line in the Disney+ version of the episode. (00:02:40)
Savage Land, Strange Heart (1) - S3-E8
Audio problem: Storm's upper and lower lips are completely separated and her teeth clenched when she says "I am free!" She wouldn't be able to say the words "am" and "free" without touching her lips together. (00:12:20)
Savage Land, Strange Heart (1) - S3-E8
Audio problem: When Kazar is saying "That should hold him for a while" after trapping the T-rex in the pit, his mouth isn't moving. (00:14:46)
Savage Land, Strange Heart (1) - S3-E8
Audio problem: When Wolverine says "On the other hand...", his mouth is wide open for the entire line. (00:20:25)
Savage Land, Strange Heart (2) - S3-E9
Audio problem: Garokk's mouth is wide open when he says "The power of the Earth shall be mine!" (00:17:20)
Savage Land, Strange Heart (2) - S3-E9
Audio problem: Sauron's mouth is wide open when he says "What is happening to me?!" (00:17:50)
Dark Phoenix (1): Dazzled - S3-E11
Audio problem: When the White Queen says "She's asleep," her mouth is closed for the first word. (00:12:39)
The Dark Phoenix (2): The Inner Circle - S3-E12
Audio problem: When Wyngarde says "For new sensations, my love," his mouth is closed for most of the line. (00:12:50)
The Dark Phoenix (2): The Inner Circle - S3-E12
Audio problem: When Beast jumps off the balcony, the sound when he lands is similar to how it would sound if he was wearing shoes or boots, but he is barefoot. (00:19:00)
The Dark Phoenix (4): The Fate of the Phoenix - S3-E14
Audio problem: When Cyclops says "Then why not trust us to deal with Jean?" his mouth is completely closed. (00:03:10)
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