Other mistake: When Logan is talking to the old man in the barn, in the "This was my son's jacket, try it on" scene, he is sitting on the motorbike, and when he gets up, the bike doesn't move up on its suspension. A few seconds later, when he sits back down on the bike, the suspension sinks a lot due to the weight of his adamantium skeleton.
Other mistake: When Wolverine and John Wraith arrive in New Orleans, the street is jammed with people and the casino they find Gambit in is also completely full of patrons. Yet somehow Wolverine being thrown through a wall, his loud shouting, his slicing a fire-ladder to pieces and Gambits massive shock thrust somehow draws absolutely no attention from anyone except the main characters.
Chosen answer: Her power works by manipulating parts of the mind. Since Victor and Logan both regenerate her power can't affect them because they essentially "heal/regenerate" the part she is manipulating. Granted Prof. X threatens Logan with this in the original movies, but he is much more powerful, or could have been bluffing.