Summary

Cron scheduler miscalculates nextRunAtMs after job execution, skipping next day's scheduled run and jumping to day after (off-by-one day bug).

Steps to reproduce

1. Create a daily cron job with schedule "0 9 * * *" (9:00 AM daily)
2. Let the job execute on Day 1 (2026-02-05 09:00 AM)
3. Check the job's nextRunAtMs in ~/.openclaw/cron/jobs.json

Expected behavior

After the job executes on Day 1 (2026-02-05 09:00 AM):

• nextRunAtMs should be set to Day 2 (2026-02-06 09:00 AM)
• Job should fire on Day 2 at 09:00 AM

Actual behavior

After the job executes on Day 1 (2026-02-05 09:00 AM):

• nextRunAtMs is incorrectly set to Day 3 (2026-02-07 09:00 AM)
• Job does NOT fire on Day 2 (2026-02-06 09:00 AM)
• Gap between lastRunAtMs and nextRunAtMs is ~48 hours instead of ~24 hours

Timeline

• 2026-02-05 09:00 AM: Job fires successfully
• Gateway updates updatedAtMs to 1770253200008 (2026-02-05 09:00:00.008)
• Scheduler miscalculates nextRunAtMs as 1770426000000 (2026-02-07 09:00:00)
• 2026-02-06 09:00 AM: Job does NOT fire (skipped) ⚠️
• 2026-02-07 09:00 AM: Next scheduled run (48 hours later)

Observed state (jobs.json)

{
  "schedule": {
    "kind": "cron",
    "expr": "0 9 * * *",
    "tz": "Asia/Shanghai"
  },
  "state": {
    "lastRunAtMs": 1770253200009,  // 2026-02-05 09:00:00.009
    "nextRunAtMs": 1770426000000,  // 2026-02-07 09:00:00.000  ← WRONG!
    "lastStatus": "ok"
  }
}

Verified timestamps

# Expected next run:
2026-02-06 09:00:00 CST = 1770339600000 ms

# Actual next run:
2026-02-07 09:00:00 CST = 1770426000000 ms

# Gap: 86400000 ms = 24 hours (one full day skipped)

Environment

• OpenClaw version: 2026.2.3-1
• OS: macOS 25.2.0 (arm64)
• Node: v25.6.0
• Gateway: Running (pid 6838), no restart on Day 1

Impact

Any daily cron job can skip an entire day's execution after a single successful run. This causes:

• Missed daily reports/briefings
• Missed scheduled backups
• Missed monitoring/alerts
• Silent failures (no error logs, job just does not fire)

Related issues

• Cron scheduler skips jobs after mid-day gateway restart #10021 - Cron scheduler skips jobs after mid-day gateway restart (similar root cause)
• Cron schedule update skips next scheduled run (off-by-one day) #4586 - Cron schedule update skips next scheduled run (off-by-one day) (same symptoms)

Additional context

• Gateway did NOT restart between Day 1 and Day 2 (verified via logs)
• The updatedAtMs field was updated by Gateway after job execution (1770253200008)
• This update may trigger the same scheduling bug as described in Cron scheduler skips jobs after mid-day gateway restart #10021 and Cron schedule update skips next scheduled run (off-by-one day) #4586
• No cron execution logs for Day 2 at 09:00 AM
• Manual run attempt failed with "not-due" error (scheduler thinks next run is Day 3)