Hi Peter,
As you are trying the conversion of .pdf file to word could you conversion how exactly you are converting the files? Is that online through the website- https://cloud.acrobat.com/exportpdf or using the desktop application Adobe Reader DC?
If you are trying it oline-https://cloud.acrobat.com/exportpdf then you may change the web browser once and check. If that doesn't make changes then for testing purpose check a different internet connection.
Also, the 2nd file you are referring to was that an actual pdf file or already a converted document? Because the quality of the converted document depends on the type of pdf you start with. So for detailed description you may go through- Text is garbled in converted file | ExportPDF
Hope this helps.
Regards,
Akanchha