No. Feedburner uses Google Feedproxy, but this simply takes a note of the requests then passes them on to you own server, and it's from there that the file is served. It's the way your server is set up. Servers have to be set up for each type of file on them - html, txt, mp3, mov, etc. etc and sometimes the wrong setting gets used.
For mp3 yours is acting as a streaming server. Streaming is like the online radio stations, where the file is downloaded as it plays but isn't store other than temporarily. To the Store your files look like an internet radio station, so of course it doesn't know how long they are and can't move forward in the recording because it thinks that would be moving into the future.
As I say, it does work after a fashion from what I remember of the other issue, and it's not likely to be the reason you were removed. You can go on as you are, but it just doesn't work in all ways quite as it should.