I have similar issue, on iOS 16 and previous PDF rendering was working pretty fine. After upgrade to iOS 17+ (issue is also replicating on iOS 17.1.1), some specific fonts on PDFs are displaying as black boxes (when the font color is set to black).

@lisandr0, did your issue got solved updating iOS to the latest (17.1.1) ? For me, problem is still happening.

Problem still happening on iOS 17.2. Fonts are displaying incorrectly.