diff --git a/account_payment_purchase/models/__init__.py b/account_payment_purchase/models/__init__.py
index 1d9a05322..f2f331b5e 100644
--- a/account_payment_purchase/models/__init__.py
+++ b/account_payment_purchase/models/__init__.py
@@ -1,3 +1,3 @@
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
-
-from . import account_move, purchase_order
+from . import account_move
+from . import purchase_order
diff --git a/account_payment_purchase/models/account_move.py b/account_payment_purchase/models/account_move.py
index 52d1ba67d..feaa64878 100644
--- a/account_payment_purchase/models/account_move.py
+++ b/account_payment_purchase/models/account_move.py
@@ -1,5 +1,6 @@
 # Copyright 2016 Akretion (<http://www.akretion.com>).
-# Copyright 2017 Tecnativa - Vicent Cubells.
+# Copyright 2017 Tecnativa - Vicent Cubells
+# Copyright 2022 Tecnativa - Pedro M. Baeza
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
 
 from odoo import _, api, models
@@ -10,16 +11,8 @@ class AccountMove(models.Model):
 
     @api.onchange("purchase_vendor_bill_id", "purchase_id")
     def _onchange_purchase_auto_complete(self):
-
-        new_mode = (
-            self.purchase_vendor_bill_id.purchase_order_id.payment_mode_id.id
-            or self.purchase_id.payment_mode_id.id
-        )
-        new_bank = (
-            self.purchase_vendor_bill_id.purchase_order_id.supplier_partner_bank_id.id
-            or self.purchase_id.supplier_partner_bank_id.id
-        )
-
+        new_mode = self.purchase_id.payment_mode_id.id or False
+        new_bank = self.purchase_id.supplier_partner_bank_id.id or False
         res = super()._onchange_purchase_auto_complete() or {}
         if self.payment_mode_id and new_mode and self.payment_mode_id.id != new_mode:
             res["warning"] = {
@@ -27,7 +20,7 @@ class AccountMove(models.Model):
                 "message": _("Selected purchase order have different payment mode."),
             }
             return res
-        elif self.payment_mode_id.id != new_mode:
+        if new_mode:
             self.payment_mode_id = new_mode
         if self.partner_bank_id and new_bank and self.partner_bank_id.id != new_bank:
             res["warning"] = {
@@ -35,6 +28,6 @@ class AccountMove(models.Model):
                 "message": _("Selected purchase order have different supplier bank."),
             }
             return res
-        elif self.partner_bank_id.id != new_bank:
+        if new_bank:
             self.partner_bank_id = new_bank
         return res
diff --git a/account_payment_purchase/tests/test_account_payment_purchase.py b/account_payment_purchase/tests/test_account_payment_purchase.py
index e772c54cd..f767f898e 100644
--- a/account_payment_purchase/tests/test_account_payment_purchase.py
+++ b/account_payment_purchase/tests/test_account_payment_purchase.py
@@ -3,7 +3,7 @@
 # License AGPL-3 - See http://www.gnu.org/licenses/agpl-3.0.html
 
 from odoo import Command, fields
-from odoo.tests import TransactionCase, tagged
+from odoo.tests import Form, TransactionCase, tagged
 
 
 @tagged("-at_install", "post_install")
@@ -112,6 +112,17 @@ class TestAccountPaymentPurchase(TransactionCase):
             result and result.get("warning", {}).get("title", False), "Warning"
         )
 
+    def test_from_purchase_order_empty_mode_invoicing(self):
+        self.purchase.payment_mode_id = False
+        self.purchase.button_confirm()
+        invoice_form = Form(
+            self.env["account.move"].with_context(default_move_type="in_invoice")
+        )
+        invoice_form.purchase_vendor_bill_id = self.env["purchase.bill.union"].browse(
+            -self.purchase.id
+        )
+        self.assertEqual(invoice_form.payment_mode_id, self.payment_mode)
+
     def test_from_purchase_order_invoicing_bank(self):
         # Test partner_bank
         product = self.env["product.product"].create({"name": "Test product"})