MtG. If you set-up advanced filter to display Rare and MythicRare from Magic 2014 Core Set - you'll see a Phantom Warrior on the second page and he is uncommon.

Phantom Warrior was a Rare in the Portal and Starter sets. That's why it shows up under that filter.

It's a known issue, but it comes from the API being used to pull the card data. I'm not sure if Sebi could add further logic to fix that issue (it happens for any card that had a different rarity across different sets). He'll need to address that issue, but is currently tied up getting the long-expected trade interface upgrade finished.