I cast Blade of the Swarm choosing the 2nd mode, Opponent has 2x Perigee Beckoner in exile. One of the Beckoner was in exile after being warped, while the other was exiled after being on the board ("true exile") As the player wanting to target the Beckoner in exile from warp, I was left to guess which one that was. I guessed wrong costing me the game. It was not clear which card in exile was in exile off of the warp cast. I was on desktop Mac.