Happily coding along all of a sudden I realise my homepage is now showing blog posts and the setting to set a static home page is missing from the reading option (see screen shot).
In the database the option show_on_front was now magically set to posts as well.
Some people have said that it is because there are no pages or no public pages. However, I have pages which are also public.
I have done the following for the moment
function force_static_page(){
update_option( 'show_on_front', 'page', true);
update_option( 'page_on_front', 28, true);
}
add_action('init', __NAMESPACE__ . '\\force_static_page');