Blossom Prancer Bug
I was playing a Premier draft today and in my first or second game one of my cards bugged out (Blossom Prancer). I went to look into my graveyard and then when I went back to Blossom Prancer to select a card the client wouldn't let me choose one of my creatures/lands that I had available to me. It only allowed me to decline the option rather than choose one of my cards.
I lost my game because of this exact issue. :-(