SERVER-63606 introduced serialization between add/remove shard with setClusterParameters, and when adding a shard, it clears the cluster parameters of the replica set, and then send the parameters set in the config server to the shard. This is done to maintain consistency with respect of the parameters throughout the cluster.

After some internal discussions, we would like to change the behavior to the following: we should preserve the cluster parameters of the first replica set added into the cluster and overwrite all possible values we have set on the subsequently added shards.