Presenter publishing causes multiple duplicate slides

I am making edits and additions to a Presenter-enhanced PPT file that was created by someone else (I have the original PPCX file and audio files as well.)

After making my edits, adding some new quiz questions and adding a few bits of additional audio, I attempted to preview and publish the PPT via Presenter as a PDF.

When I do either preview or publish, the second slide (which I added nothing to) is duplicated multiple times at the beginning of the presentation and my 24 slide presentation quickly becomes an over-100 slide presentation. Yikes!

Am I missing something simple here? Could there be an issue with the original PPCX (this issue happened prior to me making my changes when I tried to preview the original PPT via Presenter and was asked to locate the original PPCX)? Everything works fine within PowerPoint, and previewing individual slides works fine as well...

I am using PowerPoint 2013 and Presenter 8 on Windows 7.

Any help would be appreciated. Thanks in advance!

- Dave