Lag in Logs

Why is there a lag in my logs that too for a particular group?
I have four kafka consumer groups out of which one group is not giving real-time logs.
There is a one hour delay in the working hours whenever I monitor them on kibana.
I have set up a kafka cluster on three nodes all of which are working fine.
Whenever I check the logs on kafka using the live logs command the logs are coming on time there is no such delay there but rebalancing is happening both on kafka and logstash as shown in logs. Following is the command ------
bin/ --topic ppt1 --group kea_user --bootstrap-server kafka1:9092