i have set new custom stock status in woocommerce as:

add_filter('woocommerce_product_stock_status_options', 'add_custom_stock_statuses');
function add_custom_stock_statuses($statuses) {
    $statuses['4_10_days'] = __( 'Διαθέσιμο από 4 έως 10 ημέρες', 'custom-stock-status' );
    return $statuses;
}

It’s working perfect for simple products but not for variable.
Once i set all variation to this new stock status, the product is display with an outofstock badge in the frontend and as outofstock in the products admin list.
Wierd thing is that the product is purchasable.

I have even tried:

add_filter( 'woocommerce_is_purchasable', 'wpsh_disable_outofstock_variations', 10, 2 );
    
add_filter( 'woocommerce_variation_is_purchasable', 'wpsh_disable_outofstock_variations', 10, 2 );
function wpsh_disable_outofstock_variations( $is_active, $variation ) {
    if (  $variation->get_stock_status() == '4_10_days' ) {
        return true;
    }
    
    return $is_active;
}

but yielded the same results.
Any clues?