Slave Island - S1-E7
Continuity mistake: When Cyclops is trying to radio Professor X from the Blackbird, there is a window immediately to Cyclops' right. When the shot changes, Jean Grey is suddenly seated on Cyclops' right. (00:20:00)
Slave Island - S1-E7
Revealing mistake: When Storm is saying "There will be thousands of them," her mouth briefly disappears from her face. (00:16:45)
Slave Island - S1-E7
Continuity mistake: When Gambit is being escorted into the Sentinel factory, he has two guards behind him on his right and left. When the shot changes, the guards have disappeared. (00:11:00)
Slave Island - S1-E7
Continuity mistake: Before the mutants ambush the guards, they are walking in a single-file line, with Sunfire in front, followed by Jubilee, Mystique, Caliban, an unnamed female mutant, and Aurora. A couple of shots later, either Aurora or her similarly-dressed twin brother Northstar is suddenly at the front of the line. (00:08:55)
Slave Island - S1-E7
Continuity mistake: When Cyclops hangs up the phone, he is standing next to a table on which the phone is located. When the shot changes, either the table has disappeared altogether or Cyclops has suddenly moved several feet away from it. (00:06:10)
Slave Island - S1-E7
Continuity mistake: Gambit and Jubilee are shown to be grouping together what appears to be several pieces of malleable rebar. When the shot changes to Gambit reassuring Jubilee that Storm is alive, he is shown to be working with a single piece of rebar. When the shot changes again, they are back to working with a bunch of rebar. (00:05:00)
One Man's Worth: Part 1 - S4-E1
Continuity mistake: When the coffee shop owner is strong-arming Xavier, he is first shown gripping Xavier by the collar of his sweater. A couple of shots later, the coffee shop owner's hand is gripping the collar from inside the sweater. (00:15:30)
Continuity mistake: Snow suddenly appears on Wolverine's shoulders when he reaches the bottom of the ski slope.
The Phoenix Saga (3): Cry of the Banshee - S3-E5
Other mistake: When the text depicting the episode name appears on screen after the opening credits, it says "The Phoenix Saga Part 2, The Cry of the Banshee." It should read "The Phoenix Saga Part 3, The Cry of the Banshee." Note: this mistake may only apply to the DVD version of the episode. The episode that appears on Disney+ correctly depicts it as "Part III." (00:02:20)
Continuity mistake: When the X-Men regain their mutant powers, Jean Grey is suddenly wearing her uniform instead of the casual outfit she was wearing when she was abducted. In the next shot and for the remainder of the episode, she is back to wearing her casual outfit.
Time Fugitives: Part 1 - S2-E7
Other mistake: When the Friends of Humanity member is going through pictures of the X-Men on his watch, Wolverine is shown to have blond hair.
Continuity mistake: When Gambit places Bella Donna's ring on the ground, she is nowhere around it. When the shot changes, the ring is suddenly right next to her. Note: this mistake may only apply to the DVD version of the episode, as the version of the episode on Disney+ does have Bella Donna there when Gambit sets the ring down. (00:18:50)
Continuity mistake: In the first establishing shot of the Assassins Guild's mansion, there is a stairway leading up to the front door. In the establishing shot of the mansion in the scene where Gambit is in Bella Donna's bedroom, the stairway is missing, and consequently the mansion's porch area isn't as high off the ground. (00:09:20 - 00:13:20)
Continuity mistake: Shortly after Wolverine, Rogue and Jean Grey enter the Thieves Guild's mansion, they fall down a trap door. However, the trap door is not there when they first enter the mansion, instead only appearing in the shot where they step on it.
Continuity mistake: The two assassins standing guard outside the Assassins Guild's mansion have swapped sides when they let Gambit in the front door. (00:09:25)
Continuity mistake: During Gambit's flashback, the chosen one for the Assassin's Guild is shown to be placing their tithe box on the stump of a tree roughly halfway between the center ring and the outer edge. When the shot changes, the tithe box has suddenly moved to the center of the stump, and the tithe box itself is suddenly wider and shorter and has rotated 90°. (00:05:00)
Continuity mistake: The amount of damage to Cyclops' uniform decreases. When his Danger Room session is first terminated, his uniform is mostly missing around his shoulders and chest. A few shots later, the aforementioned area of his uniform is not as torn up. (00:04:15 - 00:04:50)
Continuity mistake: When Magneto is saying "You are the next step in man's evolution," the lower half of Sunfire's mask is flesh-colored. (00:11:55)
Continuity mistake: Kenny's hair goes from being light-brown to blonde. (00:05:50 - 00:11:00)
Continuity mistake: When Kirkland is going through photos of Rogue, he stops on a photo of the full X-Men team. When the shot changes, the photo he is stopped at is of Rogue and Cannonball. (00:08:25)
