In the opening short "Pikachu's Rescue Adventure" in the Bellossom song and dance scene a Poliwhirl calls itself a Poliwrath. This is obviously a mistake because of the body differences between the Pokemon.
The ancient legend in the tablet is very different in both versions. In the English version, it says that the Titans of Ice, Lightning, and Fire must be stopped by collecting the three treasures and awakening the beast of the sea, and the world will turn to Ash. In the Japanese version, it says that the God of the Sea will battle the Gods of Fire, Ice, and Lightning, and will fail, thus a superior master will rise up and save the world. The last line "and the world will turn to Ash." is not in the Japanese version, as Ash's Japanese name is Satoshi, named after the creator of Pokémon, Satoshi Tajiri.