How do you catch automations that run successfully but still produce missing, partial, or duplicate results downstream?

I want a reliable way to know that every incoming booking event actually resulted in the correct downstream record, detect missing, partial, or duplicate outcomes early, before the customer.

I’m running a production automation where incoming booking events trigger downstream record creation or update to existing. The executions appear successful (green, no failed steps), but later I discover real-world mismatches — a record wasn’t created at all, was created twice, or was only partially applied. There’s no obvious error and nothing in the execution history that clearly explains what happened.

I’ve verified credentials, basic mappings, and retries. I’m not asking about adding more logs, debugging individual nodes, or handling failed executions — those cases are already visible. The problem is detecting cases where the automation looked successful but still produced the wrong outcome downstream, and knowing whether it’s safe to replay events without creating duplicates.