When exporting a PDF file using "Export Data" in Adobe Acrobat it almost always exports no field data in the FDF. The FDF data is missing despite the field names being set correctly in Acrobat. Occasionally this does work for documents but I can see no correlation between the ones that do work and the ones that don't.
Here, for example, is the PDF: https://goodcms.s3.ap-southeast-2.amazonaws.com/staff_profile.pdf
But no matter what we do the FDF file is devoid of field name information, despite having field names in Acrobat: https://goodcms.s3.ap-southeast-2.amazonaws.com/staff_profile.fdf
This seems to happen with some PDFs and not others. The FDF flie is exported in the "export data" section of Acrobat, as outlined here https://helpx.adobe.com/acrobat/using/collecting-pdf-form-data.html
Love to get to the bottom of this - I've been trying to figure it out for months.