iSupplier contacts, when inactivated on the contacts directory, still receive the PO pdf unless end

We are finding that we need to inactivate/end date the contact the supplier contact directly and end date the contact's username name at the FND_USER table, in order for that contact to stop receiving po pdf emails.  Shouldn't inactivate/end dating the contact on the contact directly also end date the username table? 

We are on EBS 12.2.4 and using the iSupplier portal.  We do not have the supplier adding or updating their own contact information on the external iSupplier portal; we update all supplier information internally at this time.