Migrator for Notes to SharePoint

PDF file generated is blank

Hi, we're migrating a around 5000 documents from LN to SPO.  We are doing a Render with Form approach with PDF files as the output.  

Our problem is that some of the PDF files are blank and some are ok.  We thought that it was just a problem with certain LN documents.  However, when we rerun the job, a different set of PDF files are now blank.  The blank ones earlier are no longer blank.  It is not consistent as to when it happens.  Is there a configuration we're missing? 

Thanks in advance for the help.