Ticket #45235: 45235.1.diff

src/wp-includes/l10n.php

@@ -134 +134 @@
                 $determined_locale = get_user_locale();
         }
 
-        if ( isset( $_GET['_locale'] ) && 'user' === $_GET['_locale'] && wp_is_json_request() && is_user_logged_in() ) {
+        if ( isset( $_GET['_locale'] ) && 'user' === $_GET['_locale'] && wp_is_json_request() && function_exists( 'is_user_logged_in' ) && is_user_logged_in() ) {
                 $determined_locale = get_user_locale();
         }