Blog Published notification is received 2 times through email

Preconditions:

• The Mail Sending should be configured: Configure Mail Sending
• An user exists and has an email address set in its profile
• Have the Blog app installed
• Go to webapps\xwiki\WEB-INF\xwiki.properties and set notifications.emails.live.graceTime = 1 to enable the sending of e-mails after 1 minute. Make sure the line is not commented out (doesn't have an # at the start of it).

Steps to reproduce:

1. Log in as a simple user that has an email address in the profile
2. Click on the bell (Watchlist)
3. Click on Settings
4. Set EMAIL FREQUENCY > Live, DETAILS OF THE CHANGES > Standard and both Blog notifications to ON (Notification menu and Email)
5. Log in as Admin
6. Create and publish a new Blog
7. Log in as simple user
8. Check the notification from the list
9. Check the email/s received

Expected results: A notification is received that the blog was published in the Notifications list and through an email.

Actual results: User can see 1 notification in the list but he receives 2 emails at the same time, with the same content - a blog was published.