I've installed Paypal express, and it works as you say. This is a feature, not a bug. When you integrate Paypal Express, it takes the customer to the Paypal site SOLELY to approve the upcoming order, and to indicate the method of Paypal payment (credit card, from their bank, from their balance, etc).
ONLY WHEN you return to your store and hit the CONFIRM ORDER button do you see all the products and shipping details.
That is my understanding of how this works. You will not see these details at Paypal. You see them before you go to Paypal, and after you return from Paypal.
Hopefully others will correct me if I am wrong, but that is how it works on my site. I integrated this function about 3 weeks ago from the latest release.
Cheryl