Why does this PDF does not appear properly in iOS?

This PDF uses the embedded fonts Graphik-Regular and Graphik-Medium. When viewed in various readers on OS X, Windows, Android, Acrobat, the font appears correctly. When viewed in iOS, the Graphik fonts appear as a Helvetica variant. Is this a problem with iOS, or a problem with the PDF? The PDF was created using the open source library libHaru.

Here are the document font properties as seen in Acrobat