I was playing against Sparky and it was using that blue deck with fly mechanics. I was using the Cat Attack deck. It was combat phase and I had Good-FOrtune Unicorn, Felidar Savior, Dawnwing Marshal and Wary Thespian, only Dawnwing Marshal couldnt attack for summoning sickness. I had 2 unspent white mana and was preparing to use Claws Out to buff my creatures, but then during chose blockers Sparky blocked my Wary Thespian with that 1/1 Zephyr Gull and I couldnt cast my spell for it was counting as costing WW1 instead of WW.

For a reason the game counted my Wary Thespian out from the Affinity for Cats and I couldnt use the Claws Out for I didnt have the mana. Don't know why it happened, just wanted to report it.

Note: I wasn't expecting this bug to appear, so I could only record the aftermatch of the occurred.