geaoger

@lorro Thank you very much, now it works correctly. So I can close this topic as resolved.

@lorro I deleted this line :
add_action( 'woocommerce_after_shop_loop_item_title', 'wc_add_short_description' );

And now only following code left:

function wc_add_short_description() {
	global $product;

	?>
        <div itemprop="description">
            <?php echo substr( apply_filters( 'woocommerce_short_description', $product->post->post_excerpt ), 0,150 ); echo '...' ?>
        </div>
	<?php
}

But after saving, I have not short description at all.

@lorro Can you provide me more details about where should I paste your code?
If I paste it in function.php I get short description duplicates – https://i.postimg.cc/SRj8Y7Yg/screenshot-2940.png