Scheduled workflow (schedule: cron) drifted from consistent ~5-45min delay to random unrelated timings after Aug 26-27 — resolved config error but pattern persists

[prasanna8585]

🏷️ Discussion Type

Bug

💬 Feature/Topic Area

Schedule & Cron Jobs

Discussion Details

I run a scheduled monitoring workflow (.github/workflows/monitor.yml) with 6 daily cron entries spread across a ~15-hour window. For 5 consecutive days (Aug 21-25, 2026), it ran reliably — actual fire times landed 5-45 minutes after each scheduled slot, which matches GitHub's documented "best-effort" behavior and was completely acceptable.

Starting Aug 26-27, the pattern broke. Runs began firing at times with no relationship to any of my 6 configured cron slots — e.g. 00:13, 02:25, 05:21, 06:12, 18:29 IST, none of which correspond to my schedule. This coincides with GitHub's own status page
recording an Actions incident with mitigation updates around Aug 27, 00:25 UTC ("seeing recovery in Actions workflow runs and blocked pull request merges").

What I've already checked/ruled out:

• Workflow file confirmed on default branch (master) at all times
• YAML syntax validated — workflow_dispatch runs succeed consistently and immediately
• Repo has been actively committed to throughout (not hitting the 60-day inactivity auto-disable)
• Verified my own cron field values against their comments (found and fixed one config error, but the drift/scatter pattern persists independent of that fix)
• Tried the "push a trivial commit to resync" workaround mentioned in other threads — no measurable improvement

Setup:

• Private repo (considering making public to rule out Actions-minutes throttling)
• 6 schedule entries + workflow_dispatch as fallback
• Free tier personal account, several months old (not a brand-new account/repo scenario like Scheduled workflow (schedule: cron) consistently delayed 8-14 hours, one day dropped entirely — delay persists even after changing the cron minute. Related to new account/repo? #201738)

Question:
Is there a known change/incident around Aug 26-27, 2026 that caused scheduled workflow desync for existing (non-new) accounts? Discussion #201738 documents a similar pattern for brand-new accounts with a detailed explanation of low-priority batch queuing — is a similar mechanism possibly re-triggered by a platform incident for established repos, or is something else going on?

Happy to share repo/workflow name and specific run IDs (via REST API — event, created_at, run_started_at, updated_at) if that helps GitHub staff investigate.

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[masonreed11]

This sounds more like a GitHub Actions scheduling/queueing issue than a cron or YAML problem. The timing matching the Aug 27 incident, while workflow_dispatch still works normally, is a strong clue. I’d collect the affected run IDs and timestamps and report them to GitHub Support so they can check the scheduler/queue logs.