Accordingly Author spec, when the author's email is incorrect, a message saying "Please check the email syntax" should be present, but currently it's not

Steps to Reproduce

– Create a content of a Content Type that has an authors fieldtype
– On the email field, fill in with an incorrect email
– press "Publish" button

In the above actions, one can see that the email field is with a red color, with a "!" prefixed to email's field, but no message explaining the issue appears.