Good catch, this is a real bug on our end. The notification was being programmatically closed by JavaScript after 4 seconds via notification.close(). When Windows sees a notification closed by code (rather than dismissed by the user), it strips it from the notification center entirely — which is why it was vanishing without a trace.
I’ve pushed a fix that switches story notifications to use requireInteraction, which tells the browser to keep the notification visible until you click or dismiss it. That means it’ll persist in the Windows action center like you’d expect.