The issue seems to be limited only to notification messages that come for any updates on User talk pages.
- Login as user A who has a wikitext User talk page; go to the User talk page and stay on the page.
- In a different browser , login as user B and go to user A talk page to leave a message.
- For user A refresh his User talk page - the counter for Message notifications will display the count of updates(on a blue background) that user B has done.
- Click on the Message notification icon - the overlay will be displayed, and the counter will change to '0' but it'd be displayed on a blue background.
