Our customer uses Confluence 5.4 on Linux Server. He finds that some charaters in PDF file which uses Meiryo UI font are not rendered as expected. Source files are pptx and converted using Acrobat Pro XI (test case named "test.pdf" is attached).
I can reproduce this with Confluence 5.4.4 && Confluence 5.7.1.
It seems that viewfile macro can't handle correctly some attributes created Acrobat Pro XI into pdf.