fileglob lookup plugin does not search playbook dir

ansible_fileglob.txt

19:16:12 level2 [master] tree
├── file.txt
├── files
│   └── file.txt
├── hosts.yml
├── main.yml
└── roles
    └── lookup
        └── tasks
            └── main.yml

4 directories, 5 files
19:17:28 level2 [master] cat file.txt files/file.txt
Root file
files/ file
19:20:06 level2 [master] cat main.yml
---
- hosts: core
  tasks:
    - name: Import role lookup
      import_role:
        name: lookup
      vars:
        path: "{{ lookup('fileglob', '*.txt', ansible_search_path=vars.playbook_dir) }}"
19:20:09 level2 [master] cat roles/lookup/tasks/main.yml
---
- debug:
    var: path