script to hide zero price products not working with cache

Hello, I’m using this scipt to hide zero price products in search and archive woocommerce pages, sript is not working with cache:

add_filter( ‘woocommerce_product_query_meta_query’, ‘shop_only_instock_products’, 10, 2 );
function shop_only_instock_products( $meta_query, $query ) {
// In frontend only
if( is_admin() ) return $meta_query;

$meta_query[‘relation’] = ‘OR’;

$meta_query[] = array(
‘key’ => ‘_price’,
‘value’ => ”,
‘type’ => ‘numeric’,
‘compare’ => ‘!=’
);
$meta_query[] = array(
‘key’ => ‘_price’,
‘value’ => 0,
‘type’ => ‘numeric’,
‘compare’ => ‘!=’
);
return $meta_query;
}
Thanks a lot for any kind of help
Olaf