Currently the Companions & Mounts section of the WoW Armory is missing the Darkmoon Balloon, so it is not automatically being added to WarcraftPets member collections when using our Armory Import feature. Users who have acquired this pet will need to manually add it to their collections until the bug is resolved on Blizzard's end.
Also please be aware that pet collection numbers might be off by one when comparing a WarcraftPets collection to the stats in the character's armory profile, and keep this in mind before hastily reporting a false collection.
Thank you for your patience and cooperation, and we're sorry for the inconvenience this may cause. We hope the armory will be updated with the Darkmoon Balloon soon!