There appears to be an issue with the typing of flip cards from Saviors of Kamigawa block. These are the ones that start off as Monk creatures and then flip into enchantments when their condition is met. The main issue appears to be that their type is incorrectly given as "Legendary Enchantment", rather than the creature type that matches the name of the card. This causes them to sort into the enchantments section of the deck.
It's mostly a minor cosmetic annoyance for a few cards, but I've had a fair number of commander decks with two copies of a flip card because I didn't immediately see the creature I wanted to add was already in my deck in the enchantments section.