Pdf with MS SansSerif bold shows blurred, the rest ok

  • In an application we store thousands of salary forms in an historical directory. These pdfs are generated with wpcubed's wPdf3 using List&Label.
    Yesterday, on a rutinary check I realized that all the documents stored since december 2012 are not displayed correctly. After some research I´ve found out there was a small font change in the subtotal of the report that has caused this problem.
    I've tried it with the last three versiones of the viewer and with them all it displays incorrectly.
    An example pdf:
    http://www.bigun.com/Bigun/varios/Wrong.pdf
    A similar one but with different font, that displays OK:
    http://www.bigun.com/Bigun/varios/Ok.pdf

    Could you check it out, please?

    Thank you very much.