In a sense, Perhaps yes.
Consider situations where focus is not explicitly placed on the newly added or updated content. Such content may be the result of an user initiated action or otherwise. Now if that content is presented i.e. styled or positioned in a manner that certain user groups are unable to notice the change in content, that update fails to be sufficiently distinguishable. Therefore, I believe there should be a success criterion that requires newly added / updated content to be presented in a manner that it is clearly and visually discernible. Such content if not made programmatically determinable fails success criterion 1.3.1 anyway.