burrow consumergroup inconsistency

Looking at burrow metrics there's a consumergroup on __consumer__offsets that correlates to the name i've given it in the config for consumer.local but the status is STOP with lag. When checking with kafka-consumer-groups.sh I do not see it. What is the expected functionality here? Should there be a consumer running with zero lag?

Start by comparing Burrow's metrics for the configured consumer.local group with the output of kafka-consumer-groups.sh for __consumer__offsets. Trace how the STOP status and lag are derived, then document or verify the expected behavior for a configured group that is not visible to Kafka's consumer-group command.

Written by the indexing model from the issue text.