Corrupted item_id in appearance API?

Request:

https://us.api.blizzard.com/profile/wow/character/thunderhorn/daemonecum/appearance?namespace=profile-us&locale=en_US

returns in part:

{
      "id": 4294757367,
      "slot": {
        "type": "FEET",
        "name": "Feet"
      },
      "enchant": 0,
      "item_appearance_modifier_id": 4,
      "internal_slot_id": 7
    },

Since the highest item_id I’ve otherwise seen is 226019 I’m guessing there’s something wrong here?