If these are tables that you added into the data model yourself, I suspect the problem is that you used an INNER join when joining the table instead of a LEFT OUTER join.
If that is not the problem, then I would suggest opening a support ticket and attaching your data model file to the ticket so we can take a look at it. Please be sure to indicate where your new tables are in the data model (which data source, which view).
There is a support portal link in the top right of the community header. The sign in for the portal is the same as the community. Once logged in you can view or update existing requests or create a new request for help. Here's a direct link to create a request: https://support.landesk.com/CaseLogging.aspx
Here's more information on the portal Support Portal Quick Start Guide