Thanks for the good report!
I have already tested a little bit and I'm pretty sure that the problem has something to do with a filter which influences the content of the posts.
Which method do you use to place the player and the links of podPress in the posts? Do you use the [display_podcast] place-holder?
If you do not use the place holder then try set the option General Settings (of podPress) / Post Content / Location: to "End". That will probably attach "Download Standard Podcast" to the end of the iTunes:summary.
But it would be helpful for me if could tell me what this option was set to so far (and whether or not you are using the place-holder).