How to edit a form modified from a non-Acrobat product

I created a form in Word, exported to Acrobat, and added fields. I enabled extended Reader tools (form fill and save) on a form copy and gave that form to a coworker for distribution.

When the form was distributed with the extended Reader tools, document restrictions (no password) showed Changing the Document, Document Assembly, and Creation of Template Pages as Not Allowed. Usually I can Save a Copy, modify the form, and re-save a copy with extended rights again. With several of the returned forms I can no longer modify the form to change font sizes, etc., in areas where more text was entered than expected. Save a copy is not an option unless I resave as a Reader Extended pdf and then Save a Copy from there, but then only Creation of Template Pages becomes allowed again, instead of changing and assembly.

Any ideas what is causing me not to be able to edit the forms? Form data will only be presented in pdf format and is not part of a managed data process where form information becomes part of a database, so pdf appearance matters. There are multiple signature fields, but they are also not part of a managed process and it was expected to have signature errors based on the document changing from person to person.

On several returned forms I am seeing the PDF Producer as iPhone OS 11.2.5 Quartz PDF Content.  I'm assuming PDF Producer is reflecting what the program the user opened the pdf in for signature purposes.

Windows 7, Word 2010, Acrobat DC (continuous license and program updated)