Ticket #29642: 29642.diff

src/wp-includes/meta.php

@@ -985 +985 @@
                         if ( 'relation' === $key ) {
                                 $relation = $query;
 
+                        } else if (! is_array( $query ) ) {
+                                continue;
                         // First-order clause.
                         } else if ( $this->is_first_order_clause( $query ) ) {
                                 $clean_queries[] = $query;