If you're using the WordPress SEO plugin it will overwrite the theme settings for how the page title is displayed in the browser. You can adjust the title display from SEO > Titles & Metas.
To add the parent hub title to hub child page go to SEO > Titles & Metas > Post Types and in the Page text box replace the existing code with:
%%parent_title%% %%title%% %%page%% %%sep%% %%sitename%%