diff --git a/controllers/admin/AdminSupplyOrdersController.php b/controllers/admin/AdminSupplyOrdersController.php
index 862a9f639..217b15a7e 100644
--- a/controllers/admin/AdminSupplyOrdersController.php
+++ b/controllers/admin/AdminSupplyOrdersController.php
@@ -2024,6 +2024,7 @@ class AdminSupplyOrdersControllerCore extends AdminController
 		$manager = StockManagerFactory::getManager();
 		foreach ($items as $item)
 		{
+			$diff = 0;
 			if ($supply_order->is_template != 0)
 			{
 				$real_quantity = (int)$manager->getProductRealQuantities($item['id_product'], $item['id_product_attribute'], $supply_order->id_warehouse, true);