What product do you work on along with the OS?
Are you trying to add blank pages or merging PDF'?
Do you experience this with any other PDF as well?
I am using Windows 7 Professional and MS Office 2013. I am printing and Excel file to a pdf file then merging the pdf file into another pdf file. If I merge the file without using text edit it seems to be fine. When I select text edit to number pages Adobe removes the H, O or K letters in the title of each page.