The following post appeared a little while ago on the Ebay message board. It was made by someone in the company (garnor@ebay.com). It is message #92 in this thread:
http://forums.ebay.com/db2/topic/Spo...53170&start=90
Hi all, 
We are aware of an issue that is causing members to be unable to narrow down the search results within some areas in Sports Trading Cards. This is not a permanent change and we are working to resolve it as quickly as possible. 
Regards, 
Garnor