Why Does Yahoo Index My Url’s With Session Ids?

I always thought Yahoo was easier to get indexed than Google?
We changed our dynamic URLS to SE friendly ones in January. Google has finally Indexed most of them without session ID’s. However, why in the world did yahoo index our session ID urls???? Google, Yahoo and MSN dropped us for about 3 months to re-index us, so please tell me why they crawled these new urls with session id’s?

Here is an example of Google & Yahoo of the same URL

Yahoo:http://www.xxxxx.com/1/viewitem/B1303/ALLSPEC/prodinfo/session=1386208934A63812&w3path=cat

Google:url=http://www.xxxxx/1/viewitem/B1303/ALLSPEC/prodinfo/w3path=vend