Currently, if a cluster parameter validator succeeds on the config server, we expect that cluster parameter's validate and set to always (eventually) succeed on the shard servers. This check: https://github.com/10gen/mongo/blob/91a1e1241f015e592b1e1f7838230cec88b25740/src/mongo/db/change_streams_cluster_parameter.cpp#L45-L50 violates that. We are soon going to change the behavior of sharded cluster setParameter to validate ONLY on the config server to avoid issues like this in the future.