WP page loses sidebars after form submitted

I’m moving pages that were hand-coded in PHP over to live inside a WordPress blog. One of these pages is a questionnaire/poll. It’s all in one file, and depending on whether there’s POST or GET data, it will display either the questionnaire or the results.

Since there’s a lot of PHP, I did this by creating a single-page template that includes the file poll.php. I based it on the page.php file for my template. I’m pretty sure this isn’t a template-specific issue, though. The code is very simple:

<?php
/*
Template Name: Poll
Template Post Type: page
*/
get_header(); // WordPress header
?>
    <div id="container" class="<?php echo kahuna_get_layout_class(); ?>">
    
        <main id="main" role="main" class="main">
            <?php cryout_before_content_hook(); ?>
            <?php get_template_part( 'content/content', 'page' ); ?>
            
            <?php // my code
            require_once($_SERVER['DOCUMENT_ROOT'].'/pages/poll.php');
            ?>
               
            <?php cryout_after_content_hook(); ?>
        </main><!-- #main -->
    
        <?php kahuna_get_sidebar(); ?>
    </div><!-- #container -->
<?php get_footer();

My layout has a header and two sidebars. The poll page looks fine when it’s first loaded, but when the form is submitted, the results are displayed with only the header – no sidebars.

I can’t figure out why it doesn’t display the same way when the form is submitted. It’s returning to the same page, same code.

Can anyone help me?