Unfortunately it seems pdfs linked there may also be malicious ( https://www.virustotal.com/gui/url/7e73cc3d685c77d88ad9cf769... ). I checked on some other pdf links ive downloaded previously and they were safe, so I don’t believe the software just flags everything.

But it could be if the coding book includes working examples and exercises, that would probably flag any system looking for code execution.

I'm inclined to say that those are false positives, given the obscurity of the vendors who are flagging the URL.