Local action directory "fails"

gather-results.yml

---
- name: gather test results
  hosts: '{{ec2_host_group }}'
  user: '{{ user }}'
  gather_facts: True
  vars_files:
    - group_vars/all
  vars:
    results_base_path: /tmp/mysql_slap_results
    run_datetime: '{{ lookup("pipe", "date +%Y-%m-%dT%H:%M:%SZ") }}'
  pre_tasks:
    - name: create results folder
      local_action: file
        path={{ results_base_path }}/{{ run_datetime }}
        state=directory
      ignore_errors: yes
  roles:
    - gather-test-results

test output

GATHERING FACTS *************************************************************** 
ok: [redacted1.example.com]
ok: [redacted2.example.com]

TASK: [create results folder] ************************************************* 
changed: [redacted1.example.com]
failed: [redacted2.example.com] => {"failed": true, "parsed": false}
invalid output was: Traceback (most recent call last):
  File "/Users/nathan/.ansible/tmp/ansible-1380298478.27-260287155991478/file", line 1272, in <module>
    main()
  File "/Users/nathan/.ansible/tmp/ansible-1380298478.27-260287155991478/file", line 247, in main
    os.makedirs(path)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/os.py", line 157, in makedirs
    mkdir(name, mode)
OSError: [Errno 17] File exists: '/tmp/mysql_slap_results/2013-09-27T12:14:38Z'

...ignoring