When a step down occurs the recipient tries to wait for the _dataReplicationQuiesced future before deactivating the metrics state. That future is a composite of multiple futures and when any of the futures error out it would normally try to join them here. The issue is that during step down, the primary only service also shuts down the executor so the executor would refuse to run the onError and it would end up finishing the future chain without waiting for the other futures to complete.