Last night I accepted an invitation to a Duradura game. I had additional heirs that I wanted to deploy to a hard-level game, but in their open game lists they still listed the Duradura game invitation. This prevented me from joining another hard-level game. I tried joining the game again in effort to clear the already accepted invitation (game is full message), as well as refresh my browser, but the invitation was still offered. After a few minutes the situation resolved itself and I could join hard-level games on the other heirs again.