PDF text does not display properly
My coworkers made a PDF (using Acrobat Pro and MS Office on Windows) that displays properly in Windows, Mac, Android, and iPad (iOS 6). However, on two different iPhones (v3 with iOS 3, v4 with iOS 5) the PDF displays with no text and only black gradient rectangles where the first line of each paragraph should be. The backgrounds & graphics look normal.
Inspection in HexEdit and Acrobat Pro show it's in PDF 1.5 format, all fonts are embedded subset.
Any suggestions?