As per https://issues.apache.org/jira/browse/KAFKA-19607?jql=project%20%3D%20KAFKA%20AND%20text%20~%20%22Mirrormaker%22%20ORDER%20BY%20created%20DESC,, MM2 will only replicate consumer offsets if the consumer is still active or has reached the end of the partition.

If the consumer has lag, the offset translation to the target cluster can be inaccurate, and will be worse when the consumer is further away from the end of the topic (i.e. has high lag)