Hi @lextar
It is possible that you have a plugin / theme code which is modifying the post_id which ACF uses to load the value from.
Can you debug the global $post object?
<?php
global $post;
echo '<pre>';
print_r($post);
echo '</pre>';
die;
?>
Place the above code in your single PHP file. Does the $post object contain the correct ID and title?
Thanks
E