Is everyone saying "now I can't leave a duty" reading the same document I am? It says: "by intentionally leaving the game or disconnecting from the server". I don't see anywhere it says you can't use the leave duty feature, it's targeting people who quit/disconnect to avoid getting a leaving penalty.
Which is why the key points starts with "Since the game relies on internet connectivity, it is inevitable that there will be network disconnections or real-life circumstances which prevent you from playing the game. "
If you want to leave a duty, leave and take the normal wait penalty.