excess "A" letters inserted into the PDF/A format

Hi! 

I have been working with a file in Adobe Acrobat but at some stage "A":s has found their way throughout more or less the whole text, seemingly as the last of a row or paragraph.

When I open the file in any other PDF reader (microsoft edge or google chrome), the A:s remain as part of the PDF.

Has anyone seen this before? How do I remove them? Are they part of the PDF/A format or can they be removed?