To me it reads like there was a gradual rollout of the faulty software responsible for generating the config files, but those files are generated on approximately one machine, then propogated across the whole network every 5 minutes.

> Bad data was only generated if the query ran on a part of the cluster which had been updated. As a result, every five minutes there was a chance of either a good or a bad set of configuration files being generated and rapidly propagated across the network.