Logs from some of the lambda functions are not flowing through

[priyam-maheshwari]

I have the following configuration

input {
    cloudwatch_logs {
        log_group => ["/aws/lambda/a","/aws/lambda/b","/aws/lambda/c","/aws/lambda/d","/aws/lambda/e","/aws/lambda/f"]
        start_position => "end"
        access_key_id => "<access_key>"
        secret_access_key => "<secret_access_key>"
        region => "eu-west-2"
        tags => ["cloudwatch_syslog"]
    }
}

filter {
    if "cloudwatch_syslog" in [tags] {
        grok {
            patterns_dir => ["/etc/logstash/patterns"]
            match => { "message" => ["%{TIMESTAMP_ISO8601:timestampcw} > %{GREEDYDATA:message}","%{TIMESTAMP_ISO8601:timestampcw} %{GREEDYDATA:message}","%{GREEDYDATA:message}"] }
            overwrite => ["message"]
            remove_field => ["cloudwatch_logs","timestampcw"]
        }

        json {
            skip_on_invalid_json => true
            source => "message"
            target => "data"
            remove_field => ["message"]
        }
        if [data][type] != "report" {
            drop { }
        }

        else {
           mutate {
               replace => { "app" => "my-app" }
           }
        }
    }
}

output {
  if ![data] {
    elasticsearch {
      hosts => "<host>"
      user => "<un>"
      password => "<pass>"
      ilm_rollover_alias => "log_raw"
      ilm_pattern => "000001"
      ilm_policy => "log_raw"
    }
  }
  else {
    elasticsearch {
      hosts => "<host>"
      user => "<un>"
      password => "<pass>"
      ilm_rollover_alias => "log"
      ilm_pattern => "000001"
      ilm_policy => "log"
    }
  }
}

I can see the logs flowing through from lambda a,b,c and d, but no logs are seen from lambda e and f in Kibana.I have tried deleting sincedb file as well, but even after that logs are not seen. lambda e and f were added to config yesterday, whereas others have been there for quite sometime now