logic hooks on EmailAddress relationships not working?

I need to trigger a process when an Email Address is added or removed from a Contact.

I was hoping to leverage the after_relationship_add/after_relationship_delete on Contacts:

  function EmailAddressChanged($bean, $event, $arguments){
    if($arguments['related_module'] == 'EmailAddresses'){
      $bean->pending_accounting_sync_c = 1;
      $bean->save();
    }
  }

but it is not triggering at all, is the relationship to EmailAddresses not treated like other relationships?

thanks,

FrancescaS