Why don't I hear the full segment of a radio show on its podcast?

[eScotty]

I usually listen to segments of certain radio shows on the Internet, including shows on NPR, BBC and CBC, e.g., MPR's All Things Considered. I used to be able to hear a 10 or 15 minute segment of a show. But now these segments are in podcast format, and the podcast often ends right in the middle, or before the end, of the broadcast segment. Why does this happen? Is there anything I can do about this?

Thanks,
eScotty