I think this may be something unique to your RSS feeds. When I tried it with a feed from CNN, it works as expected:
I noticed that your feeds don't validate. I would suggest looking into the reason for them not validating to see if that may be causing it. Also, can you try a feed like http://rss.cnn.com/rss/cnn_topstories.rss to see if this is an environmental issue specific to your machine?