diff --git a/sale_order_type_ux/models/sale_order.py b/sale_order_type_ux/models/sale_order.py
index b101d8b1e..4ffcc6eda 100644
--- a/sale_order_type_ux/models/sale_order.py
+++ b/sale_order_type_ux/models/sale_order.py
@@ -52,5 +52,5 @@ def _prepare_invoice(self):
             so_fiscal_position = self.env['account.fiscal.position'].browse(res['fiscal_position_id'])
             if so_fiscal_position.company_id and so_fiscal_position.company_id != company:
                 res['fiscal_position_id'] = self.env['account.fiscal.position'].with_company(
-                    company.id)._get_fiscal_position(self.partner_invoice_id)
+                    company.id)._get_fiscal_position(self.partner_invoice_id).id
         return res