Not really a bug, just feedback. As a new player I find it frustrating that I keep getting Challenges to play games with Planeswalkers I haven’t unlocked yet. It would be one thing if I could just click the X and get a different Challenge immediately in it’s place. But if I click it, it just goes away with no immediate replacement. Not sure if allowing players to get these Challenges when not having access to the required characters is a sales tactic or just something that wasn’t considered in development. Either way it’s annoying.