Added "stock_lot" extra_depend.

__init__.py

@@ -7,6 +7,7 @@ from . import sale
 from . import party
 from . import configuration
 from . import stock
+from . import stock_lot
 
 
 def register():
@@ -45,3 +46,7 @@ def register():
         configuration.ConfigurationLoad,
         module='carrier_load_ul', type_='model',
         depends=['carrier_load_grouping_method'])
+    Pool.register(
+        stock_lot.LoadOrder,
+        module='carrier_load_ul', type_='model',
+        depends=['stock_lot'])

load.py

@@ -460,8 +460,7 @@ class LoadOrder(metaclass=PoolMeta):
             currency=move.currency,
             unit_price=move.unit_price,
             unit_load=move.unit_load,
-            origin=move.origin,
-            lot=getattr(move, 'lot', None)
+            origin=move.origin
         )
 
     @classmethod

stock_lot.py

@@ -0,0 +1,12 @@
+# The COPYRIGHT file at the top level of this repository contains the full
+# copyright notices and license terms.
+from trytond.pool import PoolMeta
+
+
+class LoadOrder(metaclass=PoolMeta):
+    __name__ = 'carrier.load.order'
+
+    def _get_inventory_move(self, move):
+        move_ = super()._get_inventory_move(move)
+        move_.lot = move.lot
+        return move_

tryton.cfg

@@ -9,6 +9,7 @@ depends:
 
 extras_depend:
   carrier_load_grouping_method
+  stock_lot
 
 xml:
   load.xml