Firebase queue security rule issue

Question

Expected behavior

With the recommended firebase queue security rules, see https://github.com/firebase/firebase-queue/blob/master/docs/guide.md#queue-security, a set operation should not overwrite existing tasks in the queue.

Actual behavior

Existing tasks in the queue > tasks can be overwritten with

//This overwrite the user_reminder_queue > tasks > data (This behaviour is undesirable)

//this overwrite all my data in my tasks node. I want to prevent malicious hackers from performing this overwrite. How do I prevent is through the recommended security rules
queueRef.child('tasks').set({
    'taskIdabc': {
        'message': 'happy 22: )',
        'pushKey': '-Xsdf24rasdfsdfG',
        'reminder_date': '12-12-2017',
        'hello': 'world'
    }
});

More details, check out the issue on github: https://github.com/firebase/firebase-queue/issues/109