https://uberchromegw.corp.google.com/i/chromeos/builders/master-paladin/builds/12615/steps/CommitQueueCompletion/logs/stdio

The CL in question is https://chromium-review.googlesource.com/#/c/396487/

I see this in the log, it says warning so maybe it's a red herring.
16:10:17: WARNING: A transient error occured while querying chromium-review.googlesource.com:

POST /a/changes/396487/revisions/8a5e1b587a8c8043bfd525bc07fd84ce995ac1ca/review HTTP/1.1
HTTP/1.1 409 Conflict
Response body: 'change is closed\n'


16:10:23: ERROR: <class 'chromite.lib.gob_util.GOBError'>: Conflict
Traceback (most recent call last):
  File "/b/cbuild/internal_master/chromite/lib/parallel.py", line 602, in TaskRunner
    task(*x, **task_kwargs)
  File "/b/cbuild/internal_master/chromite/lib/parallel.py", line 800, in <lambda>
    fn = lambda idx, task_args: out_queue.put((idx, task(*task_args)))
  File "/b/cbuild/internal_master/chromite/cbuildbot/validation_pool.py", line 2735, in _ChangeFailedValidation
    self.RemoveReady(change)
  File "/b/cbuild/internal_master/chromite/cbuildbot/validation_pool.py", line 2336, in RemoveReady
    self._helper_pool.ForChange(change).RemoveReady(change, dryrun=self.dryrun)
  File "/b/cbuild/internal_master/chromite/lib/gerrit.py", line 374, in RemoveReady
    label='Commit-Queue', notify='OWNER')
  File "/b/cbuild/internal_master/chromite/lib/gob_util.py", line 513, in ResetReviewLabels
    response = FetchUrlJson(host, path, reqtype='POST', body=body)
  File "/b/cbuild/internal_master/chromite/lib/gob_util.py", line 232, in FetchUrlJson
    fh = FetchUrl(*args, **kwargs)
  File "/b/cbuild/internal_master/chromite/lib/gob_util.py", line 224, in FetchUrl
    _FetchUrlHelper, sleep=SLEEP)
  File "/b/cbuild/internal_master/chromite/lib/retry_util.py", line 150, in RetryException
    return GenericRetry(exc_retry, max_retry, functor, *args, **kwargs)
  File "/b/cbuild/internal_master/chromite/lib/retry_util.py", line 100, in GenericRetry
    ret = functor(*args, **kwargs)
  File "/b/cbuild/internal_master/chromite/lib/gob_util.py", line 221, in _FetchUrlHelper
    raise GOBError(response.status, response.reason)
GOBError: Conflict