ACF Relationship Code

relationship-output.php

<?php //<~ don't add me 

add_shortcode( 'tl_related_lights', 'tl_related_lights_relationship' );
// Add Relationship ACF field between Projects and Lights
function tl_related_lights_relationship() {
    ob_start();
    
    $posts = get_field('tl_project_lights_link_used');

    if( $posts ): ?>
        <ul>
        <?php foreach( $posts as $p ): // variable must NOT be called $post (IMPORTANT) ?>
            <li>
                <a href="<?php echo get_permalink( $p->ID ); ?>"><?php echo get_the_title( $p->ID ); ?></a>
            </li>
        <?php endforeach; ?>
        </ul>
    <?php endif; ?>
    
    
    <?php
    return ob_get_clean();
}