WPML

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

Published 2026-03-27 · Updated 2026-04-06
Status
Resolved
Reported for
Advanced Custom Fields Multilingual 2.2.2
Resolved in
Advanced Custom Fields Multilingual 2.2.3
Related plugin/theme
Advanced Custom Fields
Topic tags
Compatibility

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;
		}

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