Symptoms
A specific URL was getting blocked by PCIP for some reason, so the administrator manually added the site to a URL category that is explicitly allowed. The URL is now accessible, but the page does not render correctly (images are missing) and the page format is all messed up.
Solution
The reason for this is because the page is pulling content from external web servers that are still being blocked. Using Live HTTP headers or similar, you can see GET requests for CSS style sheets and images objects getting blocked. The only workaround is to add these additional URLs to the allowed Category.