The Droplet lease timeouts were an aggravating factor for the severity of the incident, but are not causative. Absent a trigger the droplet leases never experience congestive failure.

The race condition was necessary and sufficient for collapse. Absent corrective action it always leads to AWS going down. In the presence of corrective actions the severity of the failure would have been minor without other aggravating factors, but the race condition is always the cause of this failure.