I think that this is a Safari printing problem rather than a PDF problem as such. I find that for some websites, if I print them out, I only get the first page. I need to go to one of the other browsers to be able to print out the whole site.
I suspect that if you try and print this web page (rather than make a PDF) you will find that the first page only prints, and as PDF creation is essentially just an extension of printing, this is why you are getting the PDF problem.