I had this 250 page book almost done but wanted to have the first page of each chapter without a heading. Ouch! It appears to remove the heading an page number like I want but also adds blank pages in the master document whenever it wants on a few of the added subdocuments. I can get rid of some of the blank pages by deleting page breaks where it will let me in the master document but others no. I have gone over the subdocuments that work in the master document and the ones that don’t but I can see where the error is. I will post one of the subdocuments that looksmusic dream 10 odt sample.odt good in subdocument phase but not when added to the master document.
Can’t tell without the master. In your subdoc, page style First Page transitions as expected to Default Style. Are you sure that the same page styles in the master have an identical definition?
Nothing to do with the present problem: don’t use spaces and empty paragraph to format text (refers to your “title” group). Use a dedicated paragraph style.
Assuming you are just using styles and not manual formatting. Do not forget that the default for new documents is to have the first page on the right. And LibO could insert blank pages if you inserted documents containing an odd number of pages.