Background:

You have mentioned someone in a page, now if you move the page to other page/space, you'll receive an email saying that you were assign to this "new" page/space.

Steps to reproduce:

Create a dummy user with a valid email, then mention this dummy user in a page. Now check if the workbox was updated and if there's an email there. (Expected behavior).

If yes, then move this page that you created mentioning this to other space/page. Login with his credentials and see if the workbox is mentioning the user and check if you got another email.

Workaround:

There's no workaround.

Impact:

If you're moving around 100 pages, is 100 emails that will be sent.