Custom field does not show in frontend

I already created the custom fields in function.php and I am trying to make it show in the frontend of short-description.php

The custom fields I created in function.php works perfectly in other pages (such as meta.php, etc) but it just doesn’t work on short-description.php

The code that I currently have in short-description.php is

<?php
if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly
}

global $post;
if ( ! $post->post_excerpt ) {
	return;
} ?>
<div itemprop="description">
	<?php echo apply_filters( 'woocommerce_short_description', $post->post_excerpt ) ?>

     <?php $technical_id = get_post_meta($post->ID, '_technical-drawing', true); if( !empty( $technical_id ) ){ echo '<a href="'.$technical_id.'"><img src="private/pdf.png" width="25px"></a>  Technical Drawing', ""; }?>

     <?php $instructions_id = get_post_meta($post->ID, '_operating-instructions', true); if( !empty( $instructions_id ) ){ echo '<a href="'.$instructions_id.'"><img src="private/pdf.png" width="25px"></a>  Operating Instructions', "

"; }?>

	<?php $qty_id = get_post_meta($post->ID, '_qty', true); if( !empty( $qty_id ) ){ echo '<b>Qty  </b>'.$qty_id, ""; }?>
    <?php $color_id = get_post_meta($post->ID, '_color', true); if( !empty( $color_id ) ){ echo '<b>Color  </b>'.$color_id, ""; }?>
    <?php $size_id = get_post_meta($post->ID, '_size', true); if( !empty( $size_id ) ){ echo '<b>Size  </b>'.$size_id, ""; }?>

</div>

I should also mention that the ONLY way to get my custom fields to show IS IF I post and input something in the “Product Short Description”. If I post something and save the Product Short Description, that is the only way to get the rest of the custom fields I created to show in the frontend of the page. Please help me and thank you.

If I post the same exact custom fields I created for meta.php or other frontend pages, it will show perfectly. It just doesn’t show on short-description.php

https://www.ads-software.com/plugins/woocommerce/