John - thank you for your interest!
In my tests production of incorrect blank pages is not dependent on margin sizes, eg. margins may be all set to 0mm or (say) 50mm. Also specifying a box around the chart and headers/footers has no effect. Specifying a background still produces totally blank pages.
Settings of paper size to A3, A4 or A5 produces blank pages. However, setting paper size to Legal or Letter does not produce blank pages!
I think you will agree that, whatever paper size is set, an exported PDF file should contain the same number of pages that are created and displayed in the publication preview.
I believe the problem is associated with FTM’s use of the Windows Page Setup window which is displayed from the FTM Page Setup option. The paper Sizes and Sources in the Page Setup window appear to be populated from the current default Windows Printer Driver. As explained, my tests show the problem to be independent of the available installed printer drivers. For example, if the HP Printer Driver is nominated in FTM as the PDF Driver and the paper size in Page Setup is A4 then no blank pages are printed.