APM won't load balance amongst kafka partitions

APM keeps sending event to only one partition resulting in huge lag. I have 24 partition for the topic

Kibana 7.3:

ES 7.3:

APM 7.3:

APM Agent node and v 2.x:

output.kafka:
enabled: true
hosts: ["*****:9092"]
topics:
- default: 'apm'
topic: 'apm-%{[context.service.name]}'
partition.round_robin:
group_events: 1000
reachable_only: false

As of 7.0, context.service.name was moved to service.name. Update the topic in your config and you should see events spread out.