Enclosures being deleted "automatically"

I am using PowerPress for my podcast support. I am working on some things on the web site and I swear, I set the enclosure, verify via phpMyAdmin that it is there. I don't touch anything on the site and check minutes later and the enclosure is missing. Huh?!?

Does anyone have any ideas where to start looking? I am running my own server on Ubuntu 11.x and using Apache for my web server.