ThemeREX Addons - PHP Fatal Error on Translated Testimonials Page

Overview of the issue

When using ThemeREX Addons with WPML, you might experience a fatal PHP error on translated pages that include the Testimonials widget. The error message is:
Fatal error: Uncaught TypeError: Cannot access offset of type string on string in .../wp-content/plugins/trx_addons/cpt/testimonials/tpl.default-item.php:33

Workaround

To prevent this error, make the relevant custom fields and shortcode attributes translatable.

• Go to WPML > Settings > Custom XML Configuration in your WordPress dashboard.
• Add the following XML configuration and save:

  <wpml-config>
    <custom-fields>
      <custom-field action="translate">trx_addons_options</custom-field>
    </custom-fields>
    <shortcodes>
      <shortcode>
        <tag>trx_sc_testimonials</tag>
        <attributes>
          <attribute type="taxonomy-ids" sub-type="cpt_testimonials_group">cat</attribute>
          <attribute type="post-ids" sub-type="cpt_testimonials">ids</attribute>
          <attribute>subtitle</attribute>
        </attributes>
      </shortcode>
    </shortcodes>
  </wpml-config>