As per the description above, you are getting Dutch words with a red line under it after converting a PDF to Word, Is that correct?
It seems that the fonts are not getting embedded in Word after converting the PDF to Word. To me it's not an issue with Acrobat, as in Microsoft Word, the words are getting recognized as English, not in Dutch and this is the reason you are getting a red underline under the words.
Try exporting the PDF file to Word using the URL https://cloud.acrobat.com/exportpdf and see if this brings any difference.
Try repairing Microsoft Word from control panel(for Windows), navigate to Control Panel>Program and Features>Highlight Microsoft Office>Right Click and choose "Repair". Reboot the machine and see if this brings any difference.
If the issue still persists, you may check with Microsoft support and see if they give you any suggestion
Let us know how it goes.
Thank You so much Anand Sri, it is indeed a problem with repairing Microsoft Word
Greatings Ton Zijp