I recently just completed a game. Game is over, winner declared, everyone has moved on. Except I'm still receiving Push notifications for things happening in the game. These are for things that were in progress or scheduled before the game ended, but still. When I actually open up the game (clicking Show Map on the results page), the Events tab will have a new message indicator, but when I open it, the latest message is always the game over message.

Running latest Android version.

For me, the notifications kept on going only up to the end of the day of end game.
But yeah, I agree that the notifications should be disabled after completing that game.