I am not familliar with rss reader, but I like your version.
I have registered to quite a few video feeds from the bbc news website.
I noticed that because some stories are listed in more than one of bbc's categories, I have duplicates stories in Vienna. Watching one of the duplicate doesn't mark the second duplicate as "Read"..
By duplicate I mean articles published with same title, date and link.
I tried to make a smart folder to see if it could sort this issue but may have failled in doing so.
I am not sure if it is bug report, a feature request?
Anyway I can leave with it as long as the duplicates are not multi-multiples, which forces me to sort the articles by names so that I am aware of them, and don't waste time reading/watching twice the same story.