Character encoding error
Adobe Acrobat Pro is having issues on conversions from MS Word to a PDF where it is combining characters into a single character. Most of the time it is the combination of lowercase "ti" when they show up together (e.g. Section, information, location). It functions properly in the source file of MS Word, but on the conversion Adobe combines the characters into a single character together and then doesn't recognize what character it is, throwing a Character Encoding Error. To fix you have to go into the editor, delete the combination character, and then retype the "ti" into the text editing box - which is a long process, plus you have to clean up the ADA tags afterwards on each edited text box as the editor tends to break them. Examples of the source document of a .docx that was EXPORTED to a PDF using the Adobe export engine. You can see everywhere it had the "ti" issue in the PDF.
I have suddenly encountered a similar issue where I can no longer export or print to PDF and get a readable text for certain fonts. Attached is the PDF of a PowerPoint slide that shows the problem. I'm running OS Sonoma on a Mac, with Office 365.