You can create a parameter and create a boolean filter.
See on sheet 2.
You will note also that i create all calculations i need directly in the Primary connection.
I start by bringing the Profile PY using ATTR([Profile View PY].[Profile Number PY]).
Then i create the profile type using this calculation , next the parameter and the filter.
Tableau don't seem to be able to handle a filter using a calculation pointing directly on a secondary source.
Thanks Michel. I was hoping for a more straight forward resolution, but the workaround to use a boolean filter resolves the 'business case' I was asked to demo. Definitely appears to be a bug since all functionality with the straight filter works against the secondary data source except for the renaming of Null to something else.