schema:name replaces dc:title in node title rdfa property

I've enabled the schema.org module. Now, my node title has only the schema:name RDF property and the dc:title property is not shown anymore.

I think schema:name should not replace dc:title. Instead, schema:name should be added.

The schema:name is set in schemaorg_field_ui_field_edit_form_submit().

  if ($schemaorg_mappings) {
    // Specifies the title/name mapping as expected by schema.org. This mapping
    // is always set to schema:name and is not exposed in the UI.
    // The label of an entity is usually either 'title' (e.g. node) or
    // 'name' (e.g. user).
    if (!empty($mapping['title'])) {
      $mapping['title']['predicates'] = array('schema:name');
    }
    if (!empty($mapping['name'])) {
      $mapping['name']['predicates'] = array('schema:name');
    }
...

Even after disabling the schema.org module, schema:name instead of dc:title is shown.

I think this problem is due to the handling of default mappings in the RDF module.