WPML String Translation - Strings Registered in English Even If It Is Not Default Language

Overview of the issue

When strings are automatically registered for translation in WPML String Translation, they are assigned English as the default source language, even if English is not installed or default language on the site.

Workaround

Please, make sure of having a full site backup of your site before proceeding.

• Open …/wp-content/plugins/wpml-string-translation/classes/filters/autoregister/class-wpml-autoregister-save-strings.php file.
• Look for line 67.
• Replace:

  			$domain_lang = $flag ? $this->sitepress->get_user_admin_language( get_current_user_id() ) : 'en';
  

• With:

  			$domain_lang = $flag ? $this->sitepress->get_user_admin_language( get_current_user_id() ) : apply_filters('wpml_default_language', NULL );
  

Note: please use this workaround with caution as it may bring potential performance issues.