Hi,
I think that you have the issue with the HikaShop shipping cache.
There is already the fix in HikaShop (for the new release which should be publish today or at least this week).
In the file "administrator/components/com_hikashop/classes/shipping.php" you have to replace
$order->shipping_warehouse_id = $key;
$dispatcher->trigger('onShippingDisplay', array(&$order, &$rates_copy, &$group_usable_methods, &$errors));
unset($order->shipping_warehouse_id);
By
$order->shipping_warehouse_id = $key;
$order->cache->shipping_key = $shipping_key.'_'.$key;
$dispatcher->trigger('onShippingDisplay', array(&$order, &$rates_copy, &$group_usable_methods, &$errors));
unset($order->shipping_warehouse_id);
$order->cache->shipping_key = $shipping_key;
In order to force the shipping key and do not have duplicate result with warehouses/multi-vendor.
Regards,