Advanced Custom Fields Multilingual 2.0 - Performance issues

Overview of the issue

The Advanced Custom Fields Multilingual 2.0 release may cause a considerable performance impact on your website, in both the front-end and backend.

Workaround

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

1. Open …/wp-content/plugins/acfml/classes/Strings/STPluginHooks.php file.
2. Look for line 36.
3. Change:

   		if ( $this->needsRegistration() ) {
   			Hooks::onAction( 'wp_loaded' )
   				->then( [ $this, 'maybeRegisterFieldGroupsStrings' ] );
   		} else {
   			$this->setPluginStatus( self::PLUGIN_STATUS_DEACTIVATED );
   		}
   

   To:

   		if ( ! defined( 'WPML_ST_VERSION' ) ) {
   			$this->setPluginStatus( self::PLUGIN_STATUS_DEACTIVATED );
   		}
   
   		if ( $this->needsRegistration() ) {
   			Hooks::onAction( 'wp_loaded' )
   				->then( [ $this, 'maybeRegisterFieldGroupsStrings' ] );
   		}
   

Note: you might need to reload the Custom fields settings page again.