UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.79 Safari/537.36

Example URL:

Steps to reproduce the problem:
We've been only able to reproduce this on one Windows 10 machine where the problem went away after restarting the browser, but this issue seems to come up randomly (it occurred after the user had restarted his machine entirely).

What is the expected behavior?

What went wrong?
Displaying a notification with a certain tag value does not display the notification. Changing the tag value (even just one character) or removing the usage of the tag displays the notification.

We tested this to apply to both local notifications and notifications displayed from the service worker API. This is on Windows 10.

e.g.

    var notification = new Notification("any text", {
                tag: 'notification-tag-7f061436-3199-4e09-b11a-06f8d3238996',  // This failed to display anything
              });

    var notification = new Notification("any text", {
                tag: 'notification-tag-7f061436-3199-4e09-b11a-06f8d3238995',  // Last char changed, this displayed the notification
              });

I've noticed separately of my Mac OS X 10.11.4 Chrome 50/51 (not sure which), sometimes notifications wouldn't go away when interacted with or when clicking the X button. I had to close the browser to remove the notification. I wonder if there could be a similar issue here where the notification is invisible but not going away, so using the same notification tag cannot replace the existing (invisible) notification and is causing a new one to not be displayed? 

Because we use the same tag to display notifications for a given site, the user was not able to see any notifications for a while.

Does it occur on multiple sites: N/A

Is it a problem with a plugin? N/A 

Did this work before? N/A 

Does this work in other browsers? N/A 

Chrome version: 50  Channel: stable
OS Version: 10
Flash Version: Shockwave Flash 21.0 r0