wp_get_object_terms order not working

Hi,

I’m using this function to list taxonomy terms associated to a post into a taxonomy archive page.

<?php
                        $args = array('order' =>'DESC', 'orderby' =>'term_order');

                        $product_terms = wp_get_object_terms($post->ID, 'size', $args);
						  if(!empty($product_terms)){
							if(!is_wp_error( $product_terms )){

							  foreach($product_terms as $term){
								echo '<li><a href="'.get_term_link($term->slug, 'size').'">'.$term->name.'</a><span> / </span>'. $term->description.'</li>';
							  }

							}
						  }

						?>

But it doesn’t work at all.

Into the settings page the “Auto sort” is ON.
But even if I switch to OFF it’s the same result.
Could you give me some hints?

Thank you

https://wordpress.org/plugins/taxonomy-terms-order/