WP SuperCache is caching RSS feeds. This is ok so long as the cache is cleared each time a new post is made but it isnt. As a podcaster the second I ping iTunes it looks for the new post and the enclosure data in the rss feed.
I have to turn the cache off post my podcast and then turn the cache back on. Failing to do so can cause my podcast to not be posted on itunes until hours later.
How I do stop WP Super Cache from caching rss feeds.