This looks like a good post title for general Stadia problems, so I'll just add my problems here if you don't mind ;-)
Always playing with 2 players, 2 followers. One player on Chromecast, the other player (game host) on PC / Stadia controller via HDMI.
Stadia Game Glitch / Crashes:
Several times had a crash when leaving camp, after verifying you want to camp and leave, host player screen goes back to "Waiting for other players" while other player goes back to game world as they should. I once was able to un-glitch the game after keyboard mashing. But there is no feedback from keyboard, mouser or controller while glitch is "waiting for other players".
Found that if I quicksave from F-keys then quickload from F-keys the game will restart successfully.
Can't remove duplicate main hand and ranged attack keys from hotbar.
Game glitch crashed game while trying to back out of Chromatic Orb spell selection during combat.
Others to follow when I remember them...