New session keys are never distributed when follower with key becomes leader

The expiration time for session keys starts at Long.MAX_VALUE and is updated when a new session key is read if and only if the worker is the leader. If a follower reads a session key from the config topic, the expiration time will remain Long.MAX_VALUE and, even if the worker becomes the leader, will not be updated.

Once this happens, all key rotation will cease until and unless the former leader of the cluster becomes the leader again without being restarted in the meantime, or all workers in the cluster are shut down at the same time and then the cluster is brought back up again.