diff --git a/modules/stock_package_shipping/stock.py b/modules/stock_package_shipping/stock.py
index 49d98c4a09..f4e634e7df 100644
--- a/modules/stock_package_shipping/stock.py
+++ b/modules/stock_package_shipping/stock.py
@@ -196,6 +196,12 @@ class ShippingMixin:
             ('shipping_reference', *clause[1:]),
             ]
 
+    @classmethod
+    def copy(cls, shipments, default=None):
+        default = default.copy() if default is not None else {}
+        default.setdefault('shipping_reference')
+        return super().copy(shipments, default=default)
+
     @classmethod
     def validate(cls, shipments):
         super().validate(shipments)