Hello,
The enforceSectionPageBreak option sets the section type tag as nextPage, that request the section to begins on the following page. Maybe some extra setting in the DOCX overwrites the default behaviour of the section?
We have done some quick tests with enforceSectionPageBreak and we get the correct output. Please send to contact[at]phpdocx.com the documents that illustrate your issue so we can check them and try the same script; also, as your username doesn't have any license tied, please send also the username or email that purchased the license you are using.
Regards.