Yeah, that might have done it.
That PDF file was originally meant to be opened in Adobe Reader due to the interactive elements (hovers/clicks) I put in it. If Preview was changed enough in Sierra, I suppose that could cause it to look/behave weird.
I'm slowly working on getting the Readme files online (for public viewing), and I'll look into what possibilities there are for the Maps files too (has to be behind a login). Don't have time frames for either at this point.