PayPal IPN Item Details in PayPal Transaction

[BSHRC]

ZC - 1.3.9h installed
Payment Module - PayPal IPN
Verified all Settings in ZC and PP including tokens and URLs.
Customer checkout cycle circles back to ZC from PP. ZC order has all details of payment and item details in order. However, "trans type" is different.
Working Trans Type = cart
Incorrect Trans Type = web_accept and unique

Issue - No longer seeing items in PP transactions. Had been working since initial install of ZC 1.3.8.

Last payment with desired format 01/10/11 6pm.
First occurrence of issue 01/11/11 6am.

Obviously "something" had to have changed. I know nothing was done on my site last night from an admin/file perspective but I want to double check versions.

What file is responsible for sending the call to PP with the Shopping Cart info? What categorizes the Trans Type?

I want to identify if there was a change in my ZC.
Test a rollback to previous version.
Get item details back into my PP transactions.

Any help is appreciated.