Magby was translated correctly, but was the subject of two botched rulings. The first was that its Sputter effect would end if Magby was knocked out or benched. The second was that Sputter would not stop come-into-play Pokémon Powers, such as Dark Crobat’s Surprise Bite or Entei’s Howl. (Muk’s Toxic Gas was also ruled this way.)
These terrible rulings (and many others) were the result of Wizards of the Coast not being in constant contact with Japan and also relying on employees who specialized in Magic: The Gathering to make rulings for Pokémon.
Today we of course know them to be wrong, but for a significant portion of time, these were official rulings used at tournaments. TCG ONE fortunately already has Magby and Muk programmed to work correctly; they will always stop all Pokémon Powers.
Edit: Wizards did actually have one part of Magby correct; it would not stop come-into-play powers because Sputter was intended to only affect Pokémon in play at the time of its use. Goop Gas Attack was the same way, while Muk, oddly, always stopped all Powers.