Disappearing text when applying a digital signature

Hi,

I’m hoping someone might be able to assist. I have been using Word documents for work, then converting them to PDF and digitally signing them. For about a month now, whenever I sign a document, I get a message saying “an error exists on this page. Acrobat may not display the page correctly”. All the other text (bar the digital signature) then vanishes from the PDF.

I have noticed that in the "edit PDF" setting, the "recognise text" was unticked and greyed out. However, when I forced the document to manually carry out an OCR check (by clicking on "scan & OCR", "recognise text" and then pick that file), it then allows me to sign the document with no issue. It seems that the automatic OCR has been turned off? Perhaps if the recognise text could be ticked, it may enable automatic OCR? I'm just guessing, as you can tell!  However, the “recognise text” is greyed out.

Has anyone encountered anything similar? Is there a way to turn on the OCR so it works automatically?

I am using Adobe Acrobat Pro DC (32-bit), version 2021.007.20099. I have made sure it is updated.