Hello. Can be a part of T168435 or not.

1. Open some talk page.
2. Go to the end of some section, after other user X post.
3. Answer something, did not save yet.
4. Add end of line a half line before, in X's post, just before their signature, so it will be on the new line now.
5. Save.
6. X will get a new user notice from you.

You can see here an edit of @Elitre, I just get theirs notification.