Hi, Jay -
What version/release/build of PB are you using? There have been changes to this feature with nearly every release since it was introduced in PB 2017.
Are you explicitly setting any of the NativePDF properties (see the PB Help topics that begin with "Export.PDF.NativePDF")? In particular, the default paper size for NativePDF is A4. When printed on letter-size paper, this will result in producing a blank sheet between every printed sheet.
Open the PDF in Acrobat Reader to view the properties and check the page size.
I suggest you spend a little time and examine all of the NativePDF settings.
Best regards, John
https://www.appeon.com/standardsupport/track/view?id=6504