Hi @Connor Shore ,
I have investigated this further and you are correct the issue is the macros saved in docx. You cannot save macros to a docx file. To make the .docx valid, you will need to make the fixes to the xml in document.xml described in my fix for your docm and remove all macros and related parts and relationships from the .docx file and change its ContentType to application/vnd.openxmlformats-officedocument.wordprocessingml.document.main+xml
Please let me know if this answers your questions.
Mike Bowen Escalation Engineer - Microsoft Open Specifications