UPDATE: The issue has now been resolved and PDF documents are once again displaying properly.
RSA Link (community.rsa.com) is currently experiencing an issue that is preventing PDF documents from rendering properly within RSA Link and is displaying only white space in their place.
This is a known issue that has been identified by Jive Software and their are in the process of deploying a fix to all of their customer environments, including RSA Link. This mitigation process will be complete by Friday, October 13th. For more details on the issue, please refer to the Jive Software announcement.
While this issue is occurring, users can still download the PDF documents by clicking on the file name underneath the Attachments section, as shown in the screenshot below.