If you are facing problem with YARPP (Yet Another Related Post Plugin) of duplicating content then you can try one of the method written below to fix that problem.
YARPP content duplicate problem may occur due to cache or related_post function call problems.
You can flush the cache to handle with the issue. So, go to admin page of Yet Another Related Post and add
&action=flush at the end of URL
single.php or the files where you added related_post(); of your WordPress theme and remove
echo before related_post function call
change following code
<?php echo related_posts(); } ?>
<?php related_posts(); } ?>