Ticket #51678: patch_51678.patch

wp-includes/class-wp-locale-switcher.php

@@ -189 +189 @@
          * @param string $locale The locale to load translations for.
          */
         private function load_translations( $locale ) {
-                global $l10n;
+                global $l10n, $wp_textdomain_registry;
 
                 $domains = $l10n ? array_keys( $l10n ) : array();
 
                 load_default_textdomain( $locale );
+                $wp_textdomain_registry->reset();
 
                 foreach ( $domains as $domain ) {
                         // The default text domain is handled by `load_default_textdomain()`.

wp-includes/l10n.php

@@ -740 +740 @@
         $mofile = apply_filters( 'load_textdomain_mofile', $mofile, $domain );
 
         if ( ! is_readable( $mofile ) ) {
+                $wp_textdomain_registry->set( $domain, false );
                 return false;
         }