Try this alternative way of getting the post objects. Seeing as your loop seems to be using the global post data anyway, this method uses setup_postdata
to set the global values.
$post_objects = get_field('post_objects');
if( $post_objects ): ?>
<ul>
<?php foreach( $post_objects as $post): // variable must be called $post (IMPORTANT) ?>
<?php setup_postdata($post); ?>
<li>
<a href="https://wordpress.stackexchange.com/questions/277091/<?php the_permalink(); ?>"><?php the_title(); ?></a>
<span>Post Object Custom Field: <?php the_field('field_name'); ?></span>
</li>
<?php endforeach; ?>
</ul>
<?php wp_reset_postdata(); // IMPORTANT - reset the $post object so the rest of the page works correctly ?>
<?php endif;
Reference: ACF Post Object documentation