diff --git a/l10n_br_sale/models/sale_order.py b/l10n_br_sale/models/sale_order.py
index 5fa1b5c89604..fcee00b30995 100644
--- a/l10n_br_sale/models/sale_order.py
+++ b/l10n_br_sale/models/sale_order.py
@@ -200,6 +200,12 @@ def _prepare_invoice(self):
         if self.fiscal_operation_id:
             result.update(self._prepare_br_fiscal_dict())
 
+            # By default, the value of the partner_id field should be the same
+            # as the partner_invoice_id field. The _prepare_br_fiscal_dict()
+            # method changes the partner_id value in the super result to the
+            # value of the partner_id field from the sale.order model.
+            result["partner_id"] = self.partner_invoice_id.id
+
             document_type_id = self._context.get("document_type_id")
 
             if not document_type_id:
diff --git a/l10n_br_sale/models/sale_order_line.py b/l10n_br_sale/models/sale_order_line.py
index f1350b50be28..139610bb8df9 100644
--- a/l10n_br_sale/models/sale_order_line.py
+++ b/l10n_br_sale/models/sale_order_line.py
@@ -67,7 +67,7 @@ def _fiscal_operation_domain(self):
 
     partner_id = fields.Many2one(
         comodel_name="res.partner",
-        related="order_id.partner_id",
+        related="order_id.partner_invoice_id",
         string="Partner",
     )