I am also having a problem with chapter numbering in page numbers. I have documents with a page number in the footer in the form <chap>-<page>. With Office 2007 there was no problem. I was upgraded to Office 2013, and in a document that contains more than one chapter, the page numbers for the second chapter and up contain the chapter number-1, i.e. in Chapter 6 the page numbers start with 5-. The chapters are separated by section breaks, and each chapter starts with a chapter title and Heading 1.

I was the pilot for our department upgrading to Office 2013, but due to this bug we are probably not going to upgrade to Office 2013, and I will be returning to Office 2007 shortly.