I set 'Enable strict RFC2616 etc.' as 'Yes' at that time.In your case: go to your s9y configuration screen and set the option "Strict RFC2616 RSS-Feed compatibility" to true. This will prevent updated articles to show up again in your RSS feed.
Blog is http://transblawg.eu
Today at 11.59 CET I posted an entry 'Translating Freud / Freud ins Englisch übersetzen'. Later, at 16:00, I reposted it after correcting the header to 'ins Englisch*e* übersetzen'.
On both occasions, it appeared at www.jurablogs.de, which publishes German lawblog feeds.
Am I doing something wrong?
TIA
Margaret