Odd problem with Typepad RSS feeds

Is it just me, or has anyone else noticed that Typepad hosted blogs appear to be remarkably profligate in the way they regenerate their RSS feeds? Last weekend, in what has become typical, I opened up my news aggregator, which is Radio, to discover approximately 1,000 items eagerly awaiting my attention. Of those 1,000 items, nearly half were items repeated multiple times from Typepad sites.

I can’t quite figure out whether this is an interaction between the way Radio and Typepad work or whether it is something more specific just to Typepad. Sure, it would help if I could tell Radio to only poll a site once or twice a day instead of once an hour. But on other sites, Radio appears smart enough to now pull a feed if nothing has changed since the last time it polled a site.

What is it about the way Typepad generates, or regenerates, its RSS feeds? Can someone enlighten me?

UPDATE: Mark Paschal suspects this may be related to the way that Radio handles RDF feeds. And Jenny Levine has also noted the same kinds of problem. For those with more knowledge of these things, here are some typepad feeds that illustrate the problems Jenny and I are encountering: