Usually depends on the impact. If it's one of many instances behind a load balancer and was easily fixed with no obvious causes, then we move on. If it happens

Usually depends on the impact. If it's one of many instances behind a load balancer and was easily fixed with no obvious causes, then we move on. If it happens again, we have a known short-term fix and now we have a justified reason to devote man-hours to investigating and doing a post-mortem.