Duplicate articles in navigation

Hi Guys,

I do hope you are well, I have a problem I am hoping someone can resolve:

I have a blog I am working on which shows the articles from that category in the right navigation e.g.

https://www.home-weightloss.com/category/weight-loss/tips/

However for some reason the code is showing them all twice, strangly it works here: https://www.home-weightloss.com/category/reviews/products/ but all the other categories are duplicated.

The code I am using is:

<?php global $post;
$categories = get_the_category();
foreach ($categories as $category) :
?>
<ul>
<?php
$posts = get_posts('numberposts=20&amp;category='. $category->term_id);
foreach($posts as $post) :
?>
<li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
<?php endforeach; ?>
<?php endforeach; ?>
</ul>

Thanks for your time.

Andy