The other day I was playing Duels and two of my three card pools for adding to my deck were identical. I am not certain this is a bug really, but it seems like this should not be possible, since it effectively only gives the player two choices when there should be three choices. I have a screenshot I would upload if I knew how to add pictures to the post. I was playing warlock and the card pools were both labeled In Control and contained Twilight Drake, Valdris Felgorge, and Mountain Giant.
I also got a repeated pool with mage. The same three cards.
Hate to necro, but this is still a thing. Just occurred to me.