not necessarily but keep group togther might be causing a page break along with a page break set in the sectino expert causing a blank page.
I have found that a blank page is usually from 2 things.
1. new page after is set on 2 different places int eh section expert casuing two page breaks leaving a blank page between them
2. A section that spills over just slightly onto a new page, does not actually print anything but caused a new page to be created and then the has in the section expert new page after set ont hat same section.
Look in preview mode to see if you can see what sections are indicted as being printed on the blank page.