Mac pdf reader for windows. It is becuase of 'Mirror Margin' which is set for Multiple Pages of section. Mirror Margin makes your document like a book. So each left page should have a right page with mirrored margin too. So if you have only one page in your section, the word created a second page for it to be able to manage mirrored margins P.S - Important: It is also completely related to at which number the section is started with.
Separate each page or range with a comma or space (such as '4, 7, 15-34, 56'). Non-consecutive pages and a page range specified in the Print Range section of the Print dialog box. Click OK or Print.
If all the sections use 'Continue from previous section' there would be no any blank pages but if one of the sections is defined to start with an odd page number and previous section finished with an even page number, MS Word will produce a blank page between these two ssections.