We're aware that some players still experience the permission popup issue. As this bug has been fixed by Facebook team and it doesn't affect all players, we assume that the issue is solved.
You should be able to see "Don't show again..." checkbox when you send requests. Please note that you might need to give permission to your friends once more because of this permission issue on Facebook, however, after you have successfully given permission to everyone, you shouldn't see the popup anymore.
Enjoy the game and have a nice day!