Hello Charles,
Can you be specific which app this is happening in? The feed looks ok.
So we are on the same page, the iOS podcast app uses the content:encoded field if set (it is not set in your feed) then falls back to the iTunes summary. If you do not enter a specific iTunes summary for the episode, the blog post content is used.
If you have a custom value in the iTunes summary field in the episode box and that value is not in the feeds iTunes summary field, then there is a bug. I am testing for this now and do not see an issue but I am trying a few things to try to reproduce.
--angelo