diff --git a/src/Propel/Generator/Builder/Om/QueryBuilder.php b/src/Propel/Generator/Builder/Om/QueryBuilder.php
index b8511f96e..aad1cc89a 100644
--- a/src/Propel/Generator/Builder/Om/QueryBuilder.php
+++ b/src/Propel/Generator/Builder/Om/QueryBuilder.php
@@ -2186,7 +2186,7 @@ protected function doOnDeleteSetNull(ConnectionInterface \$con): void
                         $columnL = $table->getColumn($columnNamesL[$x]);
                         $script .= "
             \$query->add(" . $refTableTableMapBuilder->getColumnConstant($columnFK) . ', $obj->get' . $columnL->getPhpName() . "());
-            \$updateValues[" . $refTableTableMapBuilder->getColumnConstant($columnFK) . "] = null;
+            \$updateValues['" . $columnFK->getPhpName() . "'] = null;
 ";
                     }