Register Contributions where the contributing attribute is from a joining connector?

Is it possible to call register-contribution in an adaptor PowerShell schema, where the source field is not from the base connector, but a joining connector?

I have been working on fixing the Register-contribution functions in a customer environment, however some of the values that are imported and are eventually used for time offset flag calculations, are coming from a non-base connector using the "Join on" transformation.

When I test using an imported change from the base connector, the changes are schedule for the correct time. When I test using an imported change a joining connector, my test fails (the imported change flows to the adaptor but does not appear to register the future change). This leads me to the conclusion that maybe an imported change from joining connector does not register future changes.

Is this correct? Is there a solution given termination/end dates required for some of the calculations, are not currently available on the base connector?