Unique "Tag" field doesn't prevent appending of notification

[Hyperion]

Example of notification:

var notice = new Notification(name, {
    body: text,
    icon: picture || 'content/images/app.png',
    tag: Math.random().toString(36).substr(2, 9)
});

But on arch linux with KDE Frameworks 5.24.0, libnotify 0.7.6, electron 1.3.1 notifications still merge into one.