Continuity mistake: Rogue rips off Donald Pierce's cybernetic left arm, but when he is first shown running away, his right arm is the one that is missing. When he catches up with Sebastian Shaw in the secret passageway, his left arm is back to being the one missing.
Continuity mistake: Wolverine first enters the sewers by ripping away a fence in the subway. When Jubilee and Gambit follow him, the fence is still intact. When they get closer it is torn again. Odd, really, because on the whole this show has few continuity errors, like self-mending clothes in other cartoons.
Factual error: When Moira is calling her ex-husband Joe in Edinburgh from the Blackbird phone, she dials a typical U.S. seven-digit phone number (it looks like she dials 555-1238). However, even assuming she wouldn't be required to dial an exit code from the Blackbird, a typical Edinburgh phone number would have more digits, along the lines of +44-131-XXX-XXXX.
Bishop: I should have known better than to play poker with an assassin.
Gambit: Shut up fool! [Throws a kinetically charged card at Bishop to no effect.]
Bishop: I can absorb your bio-energy and channel it right back.
Wolverine: I think he's getting ready to raise you.
Bishop: [Shoots an energy blast at Gambit which he narrowly avoids.] That's my mutant power.
Wolverine: [Extends his claws in Bishop's face.] How would you like to try absorbing these? Now sit down, both of you, or cards won't be the only thing that gets cut around here.