Looks like some how the variable "kafka.timeline.metrics.host_in_memory_aggregation" is not being substituted properly or the following attribute is not correct on the broker host:

# grep 'host_in_memory_aggregation'  /etc/kafka/conf/server.properties 
kafka.timeline.metrics.host_in_memory_aggregation=false
kafka.timeline.metrics.host_in_memory_aggregation_port=61888
kafka.timeline.metrics.host_in_memory_aggregation_protocol=http

.

In My default Ambari 2.7 + HDP 3.0 (with Kafka installed) i do not see any such issue in kafka logs.

So may be in your case the "/etc/kafka/conf/server.properties" file of kafka broker does not seem to be having the correct property substituted. Please try setting the value to "true" or "false" from ambari UI and test again.