I use PdfBox to insert a little bit of text at the top of my PDF-documents. I have found one case (one input document) where the resulting document appears to become semi-corrupted by PdfBox.
I will try to attach to this Jira issue a zip file with the PDF document in case and a small, self-contained Java application that allows you to easily reproduce the problem.
The text I try to insert is inserted okay and is not the problem. The problem is that other parts of the documents seem to get destroyed. You see this by comparing the original document with the processed document in a PDF document viewer.
The problem manifests itself in different ways depending on which PDF document viewer application I use. I have tried Evince (comes as default on Ubuntu Linux 14.04), Firefox (also as default in Ubuntu), Google Chrome, and Adobe Acrobat Reader v.11 (both on Windows 7 Enterprise and in Ubuntu with Wine, the Windows emulator).
I you use for example Adobe ACrobat Reader, look in particular for the logo image in the upper right corner of both pages, the fonts and the formatting of the line on the second page near the bottom that says "Fakturasum: 2 572,50".