[CLIENT] Cannot select a champion as a mission reward

As a mission reward, I was given a choice of champions. However, when I moved my mouse over a champion, to hit the select button, the select button disappeared entirely, until I hovered over the champion again. This soft-locked my game, as the only way to progress beyond this screen is to select a champion. I tried reloading the game multiple times, and I uninstalled and reinstalled the game, however nothing seems to work. At the current moment, I am unable to play, or even look at my stats, as this is the first thing that pops up when opening the game.