Pipelines not being created after push on CE nightly

On dev running 12.1.6+rnightly.122230.a589a0ca-0 (569ede33), @balasankarc pushed a branch, but pipelines were not triggered in https://dev.gitlab.org/gitlab/omnibus-gitlab/pipelines.

In the logs, I see the PostReceive job finished:

{
  "severity": "INFO",
  "time": "2019-08-17T05:47:32.262Z",
  "class": "PostReceive",
  "args": [
    "project-283",
    "user-218",
    "0000000000000000000000000000000000000000 8bd3bfc394d19ba4fa7f183b19ad274577b27b77 refs/heads/balu-update-nginx-1-16-1\n",
    {}
  ],
  "retry": 3,
  "queue": "post_receive",
  "jid": "0df642b9854b08d65d0ad00b",
  "created_at": "2019-08-17T05:47:31.743Z",
  "correlation_id": "95f8c90c-3168-4b82-a662-da8714add720",
  "enqueued_at": "2019-08-17T05:47:31.744Z",
  "pid": 54424,
  "message": "PostReceive JID-0df642b9854b08d65d0ad00b: done: 0.517 sec",
  "job_status": "done",
  "scheduling_latency_s": 0.001,
  "gitaly_calls": 3,
  "gitaly_duration": 7.97,
  "rugged_calls": 6,
  "rugged_duration_ms": 12.52,
  "duration": 0.517,
  "completed_at": "2019-08-17T05:47:32.262Z"
}

If I search by correlation_id, these are the jobs I see:

# grep 95f8c90c-3168-4b82-a662-da8714add720 current | jq ".class"
"PostReceive"
"UpdateMergeRequestsWorker"
"UpdateMergeRequestsWorker"
"ProjectCacheWorker"
"CreateGpgSignatureWorker"
"PostReceive"
"Namespaces::ScheduleAggregationWorker"
"ProjectCacheWorker"
"CreateGpgSignatureWorker"
"Namespaces::ScheduleAggregationWorker"
"UpdateProjectStatisticsWorker"
"Namespaces::ScheduleAggregationWorker"
"UpdateProjectStatisticsWorker"
"Namespaces::ScheduleAggregationWorker"

Pipeline workers aren't listed there.