Advanced Custom Fields - Fatal error when saving nested options fields in secondary languages

Overview of the issue

When using Advanced Custom Fields with ACFML, you might experience a fatal error when saving nested fields on ACF options pages in a secondary language.

Fatal error: Uncaught TypeError: md5(): Argument
#1 ($string) must be of type string, array given in .../wp-content/plugins/acfml/classes/Strings/Package.php:174

Workaround

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

• Open the …/wp-content/plugins/acfml/classes/Options/EditorHooks.php file.
• Look the registerFieldTranslation function around line 308.
• Replace:

  		if ( null === $originalValue || false === $originalValue ) {
  			return;
  		}
          

• With:

  		if ( null === $originalValue || false === $originalValue || ! is_scalar( $originalValue ) ) {
  			return;
  		}