get_permalink doesn’t output anything, it returns the permalink. Your first call works because you use it within the_title, which echos its value along with any before and after parameters you pass to it.
Change your second instance to:
<?php echo get_permalink(); ?>
or use the_permalink, which echos the value instead of returning.
<?php the_permalink(); ?>
Many functions within WordPress follow this same pattern, get_ vs. the_, one returns for use within php, one prints to page.