Ansible include_tasks未按文档搜索路径查找文件的问题

根据Ansible文档说明，include_tasks应按以下顺序查找任务文件：当前角色tasks目录、父角色目录、最后是playbook目录，但实际测试中并未出现该行为。

复现场景 #

目录结构：

├── playbook.yml
└── roles
    ├── parent
    │   └── tasks
    │       ├── main.yml
    │       └── callback.yml
    └── child
        └── tasks
            └── main.yml

playbook.yml

---
- hosts: all
  gather_facts: false
  roles:
  - parent

parent/tasks/main.yml

---
- include_role:
    role: child

child/tasks/main.yml

---
- include_tasks:
    file: 'callback.yml'

parent/tasks/callback.yml

---
- debug:
    msg: "HELLO from callback.yml"

执行结果与错误 #

执行命令 ansible-playbook playbook.yml 时，预期能找到父角色的callback.yml并输出HELLO信息，但实际报错：

TASK [child : include_tasks] *******************
task path: /home/cloud-user/test/roles/child/tasks/main.yml:5
fatal: [host]: FAILED! => {
    "reason": "Could not find or access '<path-to-playbook-folder>/tasks/parent_tasks.yml' on the Ansible Controller."
}

排查信息 #

添加-vvvvv参数后，输出的ansible_search_path显示已包含父角色路径，但仍无法找到文件：

TASK [child : debug] ******************
task path: /home/cloud-user/test/roles/child/tasks/main.yml:2
ok: [host] => {
    "ansible_search_path": [
        "/home/cloud-user/test/roles/child",
        "/home/cloud-user/test/roles/parent",
        "/home/cloud-user/test/roles/child/tasks",
        "/home/cloud-user/test"
    ]
}

已尝试使用tasks/callback.yml路径及fileglob查找方式，均无效。

疑问 #

请问是我对文档中搜索路径的理解有误，还是Ansible本身存在问题？

内容的提问来源于stack exchange，提问作者John Elion