Man, that last one took so long I stopped the browser and hit "Submit Changes" again.  Only one copy of the comment showed up, which is good.

Nice:  SF is generated email to me each time the patch is updated.  Unfortunately, I *suspect* this email goes only to the submittor, not also to the "assigned to" person.  Check that later.

What else ... mysterious "close_date" records showing up in the Patch Change History.