8 – Webform clone translation and caching issue

when i clone a webform programmatically i loose the translation.
This is my code.

//Load webform to duplicate
  $webform = Drupal::entityTypeManager()->getStorage('webform')->load($default_template);

  //Create duplicate
  $webform_duplicate = $webform->createDuplicate();

  // $webform_duplicate->set('langcode','en');
  $webform_duplicate->set('description','Event Registration GR Form for '.$title);

  //Save duplicate

Webform is created with out any problems but there is no translation and when i check in the config db table there is nothing there too.
When i search for the template i can see that there is a config row-record / collection : language.el that corresponds to the translated version of the default template.
I tried to add programmatically a translation with this code

  $result = Drupal::database()->select('config', 'c')
  ->fields('c', ('collection', 'name', 'data'))
  ->condition('c.name', 'webform.webform.event_registration_gr')
  ->condition('c.collection', 'language.el', 'LIKE')

  while ($record = $result->fetchAssoc()) {
    $record('name') = 'webform.webform.' . $webform_duplicate->id();
      ->fields(('collection', 'name', 'data'))

Which works fine too but there is an important issue with caches.
If i do not run drush cr there is no translation for my webform.
What am i missing here?
Please can you help?
Thank you in advance!