diff --git a/addons/sale/models/sale.py b/addons/sale/models/sale.py
index 9a6b63a7d13..f6539a34173 100644
--- a/addons/sale/models/sale.py
+++ b/addons/sale/models/sale.py
@@ -587,7 +587,9 @@ class SaleOrder(models.Model):
             invoice.compute_taxes()
             # Idem for partner
             so_payment_term_id = invoice.payment_term_id.id
+            fp_invoice = invoice.fiscal_position_id
             invoice._onchange_partner_id()
+            invoice.fiscal_position_id = fp_invoice
             # To keep the payment terms set on the SO
             invoice.payment_term_id = so_payment_term_id
             invoice.message_post_with_view('mail.message_origin_link',