Hi. Usually, PDF files process fonts in many ways, for example, making subsets, so is not uncommon that can of issues with fonts when you open a PDF file on Illustrator. Just replace it with a similar font.
Thank you for your response, Marlon. I have two problems if I do this though: 1. I'm not good enough at recognizing fonts to just "replace it with a similar font." 2. It's a map with streets that fit exactly in limited space. And there's no way I'm about to zoom in and go through every text layer to try and see if anything was cropped or too long. So I really have to find another solution.