Metricbeat kafka module - consumergroup metric set does not report metrics

More info:..
I turned on debug logging for metricbeats on each kafka node. The metricbeats on each node seem like they are picking up known consumer groups ... but unfortunately like i said no events for the consumergroup metricset are being generated. For example :

On node 5 i see the following in the logs:

2017-05-03T00:21:14Z DBG  known consumer groups: %!(EXTRA []string=[BrokerTestProchain10 BrokerTestProchain15 BrokerTestProchain4Rahul BrokerTestProchain1 BrokerTestProchain6])

On node 4 i see the following in the logs:

2017-05-03T00:25:02Z DBG  known consumer groups: %!(EXTRA []string=[BrokerTestProchain5 BrokerTestProchain3Rahul BrokerTestProchain14])

no error events....