Ansible 2 variables priority

bash commands

#
# ansible 1.9.4
#
ansible-playbook -i localhost.ini playbook.yml
...
TASK: [debug var=hello] *******************************************************
ok: [localhost] => {
    "var": {
        "hello": "world"
    }
}

# 
# ansible 2.0.0.2
#
...
TASK [debug] *******************************************************************
ok: [localhost] => {
    "hello": "nobody" ← why here is nobody? It's a bug or variables priority was changed?
}

localhost.ini

[develop]
localhost ansible_connection=local
[develop:vars]
hello=world

main.yml

# group_vars/all/main.yml
---
hello: nobody

playbook.yml

---
- name: Variables test
  hosts: develop
  tasks:
    - debug: var=hello

ansible/ansible#14067