Live emails are sent only after wiki restart

Preconditions:

• The Mail Sending should be configured
• An user exists and has an email address set in its profile
• Eventually, 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 (with email address in the profile)
2. Click on the bell in the top right corner
3. Click on Settings, in the right side of Notifications
4. Set "Email Frequency" to Live
5. Set ON all the options in the Email column
6. Log in with another user or with Admin
7. Create/update/delete a page
8. Comment in another page
9. Mention the used user in the content of a page

Expected results: An email is sent to the user that has the notifications set to ON, Live.

Actual results: Nothing happens. The XWiki instances needs to be restarted and after that the emails are received. If the same steps are repeated the restart has to be done every time to receive the emails.

NOTE: Working without restart on XWiki 12.10.4