Ticket #30261: 30261.4.diff

src/wp-includes/taxonomy.php

@@ -4251 +4251 @@
 
         // Don't try to split terms if database schema does not support shared slugs.
         $current_db_version = get_option( 'db_version' );
-        if ( $current_db_version < 30133 ) {
+        if ( $current_db_version < 30133 && ! defined( 'WP_INSTALLING' ) ) {
                 return $term_id;
         }