Index: workflow.module
===================================================================
--- workflow.module	(revision 301)
+++ workflow.module	(working copy)
@@ -194,8 +194,8 @@
   $node->workflow_scheduled_date = $form_values['workflow_scheduled_date'];
   $node->workflow_scheduled_hour = $form_values['workflow_scheduled_hour'];
   
-  // call node save to make sure all saving properties run on this node
-  node_save($node);
+  // Save the change in workflow state, without affecting the node revisions.
+  workflow_nodeapi($node, 'update');
 
   return 'node/' . $node->nid;
 }