--- workflow.module.orig	2010-10-23 13:04:27.752345422 +0300
+++ workflow.module	2010-10-23 13:08:27.927825734 +0300
@@ -273,6 +273,7 @@ function workflow_comment($a1, $op) {
 function workflow_transition($node, $sid) {
   // Make sure new state is a valid choice.
   if (array_key_exists($sid, workflow_field_choices($node))) {
+    $node->workflow_scheduled = isset($node->workflow_scheduled) ? $node->workflow_scheduled : FALSE;
     if (!$node->workflow_scheduled) {
       // It's an immediate change. Do the transition.
       workflow_execute_transition($node, $sid, isset($node->workflow_comment) ? $node->workflow_comment : NULL);