Answer (1 of 14): The term “continuity error” gets thrown around a lot in reference to Trek, oftentimes erroneously.
Some of the most famous “continuity errors” can be explained with a little imagination and common sense.
WHY DOES KHAN KNOW CHEKHOV IF CHEKHOV WASN’T INTRODUCED TO STAR TREK UNTI...
PSA: There’s a special screening of Star Trek IV in San Francisco on June 13 to honor the 40th anniversary. Nick Meyer (writer/producer on IV) will be there. I’m sure he will be pleased to explain how a wizard did it.
https://www.voguemovies.com/nicholas-meyer