Same podcast episode downloads multiple times

Lately I have noticed that sometimes iTunes will download the latest episode of a podcast either a couple of times a day or will download same episode a couple of days, even up to four days, in a row. Why is this? It isn't the same podcast - say a Snap Judgement is downloaded Monday, Tuesday, Wednesday (same episode - iTunes just adds a number to the end of the file name), maybe Pop Culture Happy Hour twice in a day, TAL Monday and Tuesday. It is a pest because it is chewing into my internet allowance.

Windows 7, latest version of iTunes. Any suggestions appreciated!