I have the problem with Word and Excel documents and not only with one, but with three clients.
I have tested a Doc now with Studio 2011. It was Ok, but the same Doc was not Ok with Studio 2014.
Does this happen with all Word and Excel documents in general or only with some specific files? Maybe there is something special in the source files.
Does this happen with DOC files or also with DOCX files? If you save the DOC files to DOCX, does the issue still happen?