Steps to replicate the issue (include links if applicable):

• Subscribe to a talk page with your main user account.
• Use a test account to start a new topic on that talk page, with text that includes a ping to the main account.
• Return to the main account.

What happens?:
The action generates both a red alert and a blue notification.

What should have happened instead?:
One notification (a red alert) would have been sufficient, the same way that replies to threads that include a ping generate only a ping altert, not a reply notification.