[acdha]

> a DNS misunderstanding doesn't have a particularly large "surface area" for diagnostic purposes and it is supposed to be expeditely resolvable by standard means (ordering clients to switch to a good DNS server and immediately use it to obtain good addresses)

Did you consider that DNS might’ve been a symptom? If the DynamoDB DNS records use a health-check, switching DNS servers will not resolve the issue and might make it worse by directing an unusually high volume of traffic at static IPs without autoscaling or fault recovery.