diff --git a/tests/roles/bootstrap-host/tasks/prepare_aio_config.yml b/tests/roles/bootstrap-host/tasks/prepare_aio_config.yml
index 091bf01f99..90ce767360 100644
--- a/tests/roles/bootstrap-host/tasks/prepare_aio_config.yml
+++ b/tests/roles/bootstrap-host/tasks/prepare_aio_config.yml
@@ -41,6 +41,7 @@
     dest: "/etc/openstack_deploy/openstack_user_config.yml"
     config_overrides: "{{ openstack_user_config_overrides | default({}) }}"
     config_type: "yaml"
+    list_extend: false
   tags:
     - deploy-openstack-user-config