I was playing an arena cube game on PC a few minutes ago and had Grenzo on board. At the beginning of my upkeep the heist triggers, and show three cards. I go back to the board to check before making my pick to make sure I had Zaelous Conscript exiled with Ashiok and do some math (the game was tight) and when I clicked to come back to the heist selection I couldn't see the cards. I tried to go back and forth to resolve the issue but nothing happened, and it endeded up skipping my turn due to timeout. My opponent won on the spot. It cost me a loss during a paid event.