I've noticed that every time I log in, the tavern gives me a purple and gold card available but I never seem to get it. I decided to test it out, and it turns out that if you don't hit shuffle and refresh instead, the purple and gold card will appear (course you can never actually get them).

So basically tynon is showing us some fake cards in order to make us play with the tavern more. I suggest you guys never spend gems for extra flips for the cards that appear when you log in.