diff --git a/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovsdb_monitor.py b/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovsdb_monitor.py
index 8628847d52a..d43973e134d 100644
--- a/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovsdb_monitor.py
+++ b/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovsdb_monitor.py
@@ -82,6 +82,11 @@ class ChassisEvent(row_event.RowEvent):
         if not self.driver._ovn_client.is_external_ports_supported():
             return
 
+        # NOTE(lucasgomes): If the external_ids column wasn't updated
+        # (meaning, Chassis "gateway" status didn't change) just returns
+        if not hasattr(old, 'external_ids') and event == self.ROW_UPDATE:
+            return
+
         is_gw_chassis = utils.is_gateway_chassis(row)
         # If the Chassis being created is not a gateway, ignore it
         if not is_gw_chassis and event == self.ROW_CREATE:
diff --git a/neutron/tests/unit/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_ovsdb_monitor.py b/neutron/tests/unit/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_ovsdb_monitor.py
index ac5ad29a8c1..3d21d458cec 100644
--- a/neutron/tests/unit/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_ovsdb_monitor.py
+++ b/neutron/tests/unit/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_ovsdb_monitor.py
@@ -558,3 +558,12 @@ class TestChassisEvent(base.BaseTestCase):
         # after it became a Gateway chassis
         self._test_handle_ha_chassis_group_changes_create(
             self.event.ROW_UPDATE)
+
+    def test_handle_ha_chassis_group_changes_update_ext_id_not_found(self):
+        self.is_gw_ch_mock.side_effect = (True, False)
+        old = fakes.FakeOvsdbTable.create_one_ovsdb_table(
+            attrs={'name': 'SpongeBob'})
+        self.assertIsNone(self.event.handle_ha_chassis_group_changes(
+            self.event.ROW_UPDATE, mock.Mock(), old))
+        self.assertFalse(self.nb_ovn.ha_chassis_group_add_chassis.called)
+        self.assertFalse(self.nb_ovn.ha_chassis_group_del_chassis.called)