Can't render PDF form with prefilled data

I am new to LiveCycle and have recently run into issues with using the renderpdfform service. 

I am currently building a form and workflow approval process.  After the user fills out and submits a questionnaire in Workspace, the next PDF form should open up with prefilled fields from the questionnaire via the process shown below:

As you can see, this can be started either programmatically or from the xml file containing the questionnaire data being dropped into a watched folder. 

Here is my renderpdfform service configuration:

Form - URI = Forms/XForm.xdp

Form Data - inpDoc variable (contains xml data)

Target Url - (url for my approval process)

RenderedForm - docRenderPDF variable

Here is my issue - whenever I try to run this process without the prefilled data (i.e. no Form Data variable defined in the Input of the configuration), the blank PDF will open up in the client (browser/Workspace) with no issues.  However, as soon as I add the Form Data variable with the xml data, I can't get it to render to the client anymore.  But when I record the process, I can see in my recording that docRenderPDF clearly contains the prefilled data; it just doesn't show up in the client. I'm not exactly sure why this is happening - any help is truly appreciated.