Embed is showing "Protected" on fillable PDF

Hi,

We're testing out the PDF Embed API for displaying PDFs. 

Several of our PDFs are fillable and printable. The properties on these PDF documents show they do have Password Security enabled, but Printing/Content Copying for Accessibility/Filling of Form Fields/Signing/Creation of Template Pages are allowed. And document assembly, content copying, page extraction and commenting are disabled.

When we load these using the PDF Embed API, they show as "Protected" in the title bar at the top, and the fillable fields are not displaying (even though "Filling of Form Fields" is enabled on the PDF).

What are the conditions for the document displaying "Protected" and not showing the fillable fields?

Thanks!