Scheduled workflows are not triggering, but manual runs succeed

[arapapa77]

🏷️ Discussion Type

Bug

💬 Feature/Topic Area

ARC (Actions Runner Controller)

Discussion Details

Hello,

I am investigating a GitHub Actions scheduling issue in my private repository. Manual workflow runs succeed, but new scheduled runs are not appearing.

Repository and configuration

Repository: arapapa77/uptime-monitor (private)

Default branch: main

Workflow location: .github/workflows/monitor.yml

Current schedule: */10 * * * *

Runner: ubuntu-latest

Observed behavior

As of October 2, 2026, approximately 16:45 KST (07:45 UTC):

The latest scheduled run shown for the original workflow started at 11:10 KST (02:10 UTC).

That run failed during the final step that pushes status.json back to the repository.

I fixed the push issue, and subsequent manual runs completed successfully.

No new scheduled runs have appeared since the 11:10 KST run. There are no new scheduled runs shown as queued or failed either.

Troubleshooting performed

Verified that the workflow file is saved on the default branch, main.

Verified the YAML schedule configuration.

Tried 30-minute schedules and then restored the original 10-minute schedule.

Disabled and re-enabled the original workflow.

Confirmed that manual runs of the original workflow succeed.

Created a separate minimal workflow to test scheduling independently of the monitoring script, secrets, and Git operations.

The separate test workflow also has no scheduled runs so far. Its first manual run succeeded in approximately 10 seconds.

The test was created this afternoon, so its observation period is shorter than that of the original workflow.

Minimal test workflow

File: .github/workflows/schedule-test.yml

name: Schedule Test

on:
schedule:
- cron: "3,13,23,33,43,53 * * * *"
workflow_dispatch:

permissions:
contents: read

jobs:
test:
runs-on: ubuntu-latest
timeout-minutes: 1
steps:
- name: Check scheduled execution
run: |
echo "event=${{ github.event_name }}"
date -u

Expected behavior

Both workflows should periodically receive schedule events. I understand that scheduled runs can be delayed or dropped under high load, but the original workflow has now had several hours without a new scheduled run.

Questions

Are other users experiencing similar delays or missing scheduled runs?

What additional repository or account settings should I check?

Is there a way to determine whether scheduled events are being delayed, dropped, or not generated for this repository?

I am attaching screenshots of the original workflow run list and the successful manual test run. Because the repository is private, community members will not be able to inspect its contents directly.

Thank you for your help.

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[Jyotir2004]

Most likely area

The strongest signal is that scheduled events are not being created/delivered to the repository, rather than the runner failing to execute them.

Your minimal workflow is particularly important:

on:
schedule:
- cron: "3,13,23,33,43,53 * * * *"
workflow_dispatch:

If workflow_dispatch works but schedule produces no queued, failed, or completed runs, the failure is occurring before the job reaches ubuntu-latest.

So I would investigate the GitHub Actions scheduler / scheduled-event delivery path before changing the workflow code further.

One important ARC point

You listed ARC (Actions Runner Controller) as the feature area, but your workflow uses:

runs-on: ubuntu-latest

That normally uses GitHub-hosted runner infrastructure, not an ARC self-hosted runner.

Therefore, unless your repository/organization has some special ARC configuration affecting Actions, ARC is probably not the component to troubleshoot first.

If scheduled events aren't appearing at all, an ARC runner would generally not get a job to execute in the first place.

What I would check next
GitHub Actions status
Check GitHub Status for an Actions incident around October 2, 2026, 02:10–07:45 UTC.
Pay particular attention to Actions workflow scheduling, not just runner availability.

Repository Actions settings
Check:

Settings → Actions → General

Verify:

Actions are enabled.
Workflow permissions aren't causing a repository-level restriction.
There isn't an organization policy restricting scheduled workflows.

Check the workflow's event configuration

Make sure the actual file on main is structurally:

name: Schedule Test

on:
schedule:
- cron: "3,13,23,33,43,53 * * * *"
workflow_dispatch:

permissions:
contents: read

jobs:
test:
runs-on: ubuntu-latest
timeout-minutes: 1

steps:
  - name: Check scheduled execution
    run: |
      echo "event=${{ github.event_name }}"
      date -u

Check the Actions UI filters carefully

Don't only look at failed/queued jobs. Look at All workflows → Schedule Test and check whether GitHub is creating any workflow run with schedule as the event.

Wait for multiple cron intervals

Your test schedule runs at minutes:

03, 13, 23, 33, 43, 53

So you have a useful test every 10 minutes. If several consecutive intervals pass with zero scheduled workflow records, while manual dispatch continues to work, that makes a scheduler/event-delivery problem increasingly likely.

One thing I would change in the discussion

I would avoid saying “ARC is broken” at this point. Your evidence supports:

Scheduled workflow events are not appearing, while manually dispatched workflows execute normally.

That's a much stronger and more defensible description because it identifies the observed failure without assuming which GitHub backend component is responsible.

Also, the fact that the original scheduled run failed at the final git push step is probably unrelated to the current scheduling failure, because your independent schedule-test.yml reproduces the scheduling problem without any Git operations.

If this persists across several additional schedule intervals, the most useful escalation data would be the exact UTC times when scheduled runs were expected but absent, plus the fact that both workflows fail to generate scheduled runs while workflow_dispatch succeeds.

[arapapa77]

Thank you for your detailed response and helpful suggestions.

GitHub Actions is enabled, and “Allow all actions and reusable workflows” is selected in the repository settings. As of October 2, 2026, at 19:29 KST (10:29 UTC), neither workflow has generated any new scheduled runs. Manual runs succeed for both workflows.

I have attached a screenshot of the repository’s Actions settings for reference.