Beyond Good and Evil: Part 2 - S4-E9
Character mistake: Wolverine refers to Psylocke as having black hair and Archangel refers to her as being raven-haired. She has purple hair. (00:11:55)

Starring: Alyson Court, Cathal J. Dodd, George Buza, Norm Spencer
Beyond Good and Evil: Part 2 - S4-E9
Character mistake: Wolverine refers to Psylocke as having black hair and Archangel refers to her as being raven-haired. She has purple hair. (00:11:55)

Days of Future Past: Part 2 - S1-E12
Factual error: When Gambit is inside his mini-jet after escaping from Bishop and Wolverine, his radar screen says "Washington D.C." but the graphic above it is Washington state.
Night of the Sentinels: Part 1 - S1-E1
Morph: [imitating Senator Kelly] My fellow Americans, I am an idiot.

The Juggernaut Returns - S3-E17
Trivia: When the new Juggernaut crashes through the film studio, the production being filmed is a parody of Mighty Morphin' Power Rangers. There is even a short musical phrase similar to MMPR's theme song. (00:16:10)
Chosen answer: It says MPO "First Exemplary Printing House" which is a real printing company in Russia founded by Ivan Dmitrievich Sytin in 1889. There seems to be something about "named after..." as well.
Sierra1 ★