With two clients now, we've had the same problem -- when the Delayed Page Publish job runs, it keeps re-publishing the same page. So, every 15 minutes, this page is processed by the job, even though nothing has changed on it, and it wasn't scheduled to publish.
One client had their database fill up before they found it. The other one just noticed they have almost 3,000 versions of this one page.
Both clients were on v6 R1.
Is this a known issue?