The entries in the RSS feed http://freesound.iua.upf.edu/rss.php are a few days in the future so they appear to be the newest items even as other feeds entries arrive.
the newest date seems to be set to:
which isn't in the future...
could it be a problem in your news reader?
Oh, you're right. Apparently, it expects dcate for this type of feed to be in this format: