While using Firefox on Windows, pdf.js worked beautifully. It was honestly amazing. But on (K)ubuntu, it fails to render the files - not just some, but any (which is why I'm posting here). For example, I searched for 'pdf' on Google and opened the first pdf file, and it looked like this:

All pdfs look like this, some even worse. Has anyone else had this problem? I found a few posts about terrible font rendering with pdf.js, but all those posters said it had been resolved with an update ... I have already tried disabling all addons, reinstalling Firefox (I even reinstalled Kubuntu (not because of this problem)).