Hello. I was just reliving some classic, Generation I Pokémon (in this case, Yellow Version) when I came across an NPC in the Celadon Department Store who stated that Copycat lives in Cerulean City.

In the trivia section of the article about Copycat on Bulbapedia, it mentions this error. However, I have a few additional questions.

First off, was it present in Blue/Red? I never noticed it in the past...

Also, was the mistake present in the original Japanese versions of the games? Or, was it introduced during the translation process, possibly also affecting other translations derived from the English ones?