I have talked to a Senior Applecare Advisor and after a long but very productive discussion we discovered that she had the same problem on her computer with her iTunes store account. Here is what we have found.
When you click on Purchased on the iTunes web page for TV shows the system is supposed to check your library for all, of the TV shows that have not been downloaded to your computer. It is not doing this at all. It is doing something completely different. We could not identify exactly what it was doing but at least we could identify that it was not checking for shows that have not been downloaded.
The only current method of checking for shows that need to be downloaded is to go to the Store menu in iTunes and slide down to "Check for available downloaded".
We were able to verify that it was not working by the following test.
On the left of the web page showing the available shows to be downloaded is the list of shows that have been purchased. At the top of that list is "Recent Purchases". That is the default when the page is loaded. If you click on any of the shows below that you should be able to click on the top option of "Not in my library" and the system should identify only the episodes for that show that are not in your library. It does not even do that correctly.
To sum this all up we now have an Applecare Senior Advisor that has the same problem with her account so that she can show the iTunes developers exactly what is happening. She is going to keep me posted as she identifies the issue to the developers.
I will pass on all she sends me.
