i pulled down the SNAT patch for 1650 which said it was updating the version to 1652 (not indicated in the milestone pull-down menu). in the first three (3) updates i got the following:
2 each applied the patch, but the version number displayed is still 1650.
1 each applied the patch and amongst co-processed pkg updates was webmin 1660-1.
there was a period of time between each update, so 1660-1 must have come along as i was working through.
the point: since applying the 1652 version/patch, webmin no longer recognizes its own updates in the unique way it used to: with a separate notice on the sys info page. now, new webmin versions are just found in the pkg update check ('yum' in my case) for all of the "other" pkg's.