Correct, the first page of a book usually has (or is expected to have a \mt main title) which spans across the page, and therefore a header with the book name would "spoil that layout". So traditionally, the first/intro page of a book does NOT get any header.
However, as always, there's a way to tell it that you want a header there anyway, and this would be done by adding your own .tex code as shown below to the ptxprint-mods.tex file (see Advanced tab, enable the option and then click on Edit...)
%% Title Even Header
\def\RHtitleevenleft{\rangeref}
\def\RHtitleevencenter{\book}
\def\RHtitleevenright{\empty}
%% Title Odd Header
\def\RHtitleoddleft{\empty}
\def\RHtitleoddcenter{\book}
\def\RHtitleoddright{\rangeref}
Note that you might also want to include a page number (on the inner).