Character mistake: Spock says "The Queen of Hearts and her cards are characters from Alice Through the Looking Glass, Captain." They are from Alice in Wonderland. Looking Glass has chess pieces as characters instead of playing cards.
Star Trek: The Animated Series (1973)
1 character mistake - chronological order
Starring: William Shatner, George Takei, Leonard Nimoy, DeForest Kelley
Continuity mistake: When Uhura's rescue party is in the transporter, Chapel's uniform is blue. When they materialize on the planet, it's red for a moment, then blue.
Trivia: When the animated series was being voice-cast, the only original actors chosen were William Shatner, Leonard Nimoy, DeForest Kelly, James Doohan and Majel Barrett (Gene Roddenberry's wife). James Doohan was going to double as Chief Engineer Scott and as Lieutenant Sulu, as well as any needed additional male voices; Majel Barrett was going to perform several female voices including the Ship's Computer and Communications Officer Uhura. When Leonard Nimoy (Spock) learned about the casting choices, he threatened to quit the animated series unless original series actors George Takei and Nichelle Nichols were hired to play Sulu and Uhura. Nimoy's opinion carried a lot of weight, so Takei and Nichols were immediately hired.