Yugioh actual card rules: Mirage Knight

The rules in the actual game and the anime is not always the same but in this case I was wondering in episode 113 In the end phase Mirage Knight broke down back to Dark Magician and Flaming Swordsman but no where does it say that in the actual card, is that an actual rule in the game or is it just in the anime?

that was the original effect but the errata has been changed. don't know when thought.