diff --git a/addons/point_of_sale/models/pos_order.py b/addons/point_of_sale/models/pos_order.py
index 51fdad1610b..e5da2dd479f 100644
--- a/addons/point_of_sale/models/pos_order.py
+++ b/addons/point_of_sale/models/pos_order.py
@@ -823,7 +823,10 @@ class PosOrder(models.Model):
                         'lot_id': lot_id,
                     })
                 if not pack_lots and not float_is_zero(qty_done, precision_rounding=move.product_uom.rounding):
-                    move.quantity_done = qty_done
+                    if len(move._get_move_lines()) < 2:
+                        move.quantity_done = qty_done
+                    else:
+                        move._set_quantity_done(qty_done)
         return has_wrong_lots
 
     def _prepare_bank_statement_line_payment_values(self, data):