diff --git a/addons/sale/models/account_move_line.py b/addons/sale/models/account_move_line.py
index e74f8c19dc1..43a0be53dba 100644
--- a/addons/sale/models/account_move_line.py
+++ b/addons/sale/models/account_move_line.py
@@ -118,7 +118,8 @@ class AccountMoveLine(models.Model):
 
         # create the sale lines in batch
         new_sale_lines = self.env['sale.order.line'].create(sale_line_values_to_create)
-        new_sale_lines._onchange_discount()
+        for sol in new_sale_lines:
+            sol._onchange_discount()
 
         # build result map by replacing index with newly created record of sale.order.line
         result = {}