strange box on pdf export
I'm hoping someone can help. I have rebooted, uninstalled and googled endlessly. After proofing an ai document, I did a file, save as, pdf. Normal procedure here. When I went to review the pdf, I am finding these square boxex with an X all throughout my pdf. It seems to appear on certain commas, apostrophes and single quote marks, but not on all of them. I also tried to change the font on some of these that appeared and that did nothing other than waste time. I am not missing any fonts and they are all also embedded. I'm not sure if this matters, but the original creator of the document uses a mac and I have a pc. I asked someone else (mac user) to save the pdf and it displayed perfect without any boxes for them. Seems to just be my machine. Please help me before I go crazy!
I have a sample photo below with the boses highlighted in yellow.
