Logstash does not forward logs

[d.shulinin (Dmitry)]

Hi all.
I'm facing a strange issue with logstash 7.2.0.
I have two winlogbeats with a similar config sending logs to logstash (elk-1). Logstash then sends the logs to elasticsearch node (elk-2).
I can confirm that logs from both winlogbeat hosts ("wef1" and "wef2") are reaching logstash because I have setup a file output and I do see logs from both hosts in that file. I differentiate events from these two hosts by the field "hostname" which I see in the output file.
That is I get either events with "hostname":"wef1" and "hostname":"wef2".

Next I have an output config to send the logs from logstash to elasticsearch. However when I perform search across the index in Kibana I see only events from host "wef1".

"elk-1" is the logstash node. "elk-2" is the elasticsearch node. They stand on the same network so there is no firewalling in between.

Here is my logstash config:

input {
  beats {
    port => 5045
    id => "winlogbeat-wef"
    tags => ["winlogbeat-wef"]
  }
}

output {
  if "Winlogbeat-Security" in [tags] {
    elasticsearch {
      hosts => ["elk-2:9200"]
      manage_template => false
      index => "%{[@metadata][beat]}-security-%{[@metadata][version]}-%{+YYYY.MM.dd}"}
    file {
      path => "/tmp/win_wef.log"
    }
}

Here is the beats config on both nodes:

winlogbeat.event_logs:
- name: ForwardedSecurityLog
    forwarded: true
    tags: ["Winlogbeat-Security"]
    ignore_older: 24h
output.logstash:
  hosts: ["elk-1:5045"]

Please advise how to debug the issue.
I've turned on debug log in logstash and elasticsearch but have not discovered anything specific.