As of September 1st, the Apache Cassandra community has shifted the focus of Cassandra 4.0 development from new feature work to testing, validation, and hardening, with the goal of releasing a stable 4.0 that every Cassandra user, from small deployments to large corporations, can deploy with confidence. There are several projects and methodologies that the community is undertaking to this end. One of these is the adoption of property-based testing, which was previously introduced here. This post will take a look at a specific use of this approach and how it found a bug in a new feature meant to ensure data integrity between the client and Cassandra.