In your page template line 42 you will see
<?php if ( is_archive() || is_search() ) : //display excerpts for archives and search. ?>
<?php the_excerpt(); ?>
<?php else : ?>
<?php the_content('Read More'); ?>
<?php endif; ?>
This means that there won’t be a heading on archive pages and the_excerpt doesn’t allow html like hyperlinks (though you could use a plugin “advanced excerpt” to achieve formatting in excerpts)