failed_when in Ansible

ansible 2.7.6
  tasks:
    - command: echo "123"
      register: result

    - debug: msg="{{result.stdout}}"
      failed_when: "'234' in result.stdout"

    - debug: msg="{{result.stdout}}"
      failed_when: "'12' in result.stdout"

TASK [command] *******
changed: [localhost]

TASK [debug] *******
ok: [localhost] => {
    "msg": "123"
}

TASK [debug] *******
fatal: [localhost]: FAILED! => {
    "msg": "123"
}