Bugs happen, and the effects of cascading failures are very hard to anticipate. But it seems like the aws team hadn't fully tested the effects of an EBS outage,

Bugs happen, and the effects of cascading failures are very hard to anticipate. But it seems like the aws team hadn't fully tested the effects of an EBS outage, which seems like it could have uncovered the rdms multi availability zone failover bug and perhaps the elbs failover bug ahead of time.