Parsing Error in Fortinet-Module Pipeline blasts up message log

Hey guys,

First of a few details about my cluster:

Cluster of 3 Servers - 1xMaster 2xData Nodes
All of them are running ES 7.8 Filebeat 7.8 (ofc Kibana as well on the master node)
OS: CentOS 7 (Kernel 3.10.0-957)
I noticed that there now was a Fortinet Module within Filbeat - and i decided to try it out.

Fortinet Config:

- module: fortinet
  firewall:
    enabled: true

    # Set which input to use between tcp, udp (default) or file.
    var.input: udp

    # The interface to listen to syslog traffic. Defaults to
    # localhost. Set to 0.0.0.0 to bind to all available interfaces.
    var.syslog_host: X.X.X.X

    # The port to listen for syslog traffic. Defaults to 9004.
    var.syslog_port: Y.Y.Y.Y

It works, i recieve the logs from around 15 devices. But today i noticed that my /var/log/message -file is exploding since the activation of the Fortinet-Module.

I get the following error:

{"type":"mapper_parsing_exception","reason":"failed to parse field [fortinet.firewall.assignip] of type [ip] in document with id '5l6cVnMBP7KwE6GF3kEA'. Preview of field's value: 'N/A'","caused_by":{"type":"illegal_argument_exception","reason":"'N/A' is not an IP string literal."}}
Jul 16 09:53:07 datanode02 filebeat: 2020-07-16T09:53:07.078+0200#011INFO#011[publisher]#011pipeline/retry.go:221#011retryer: send unwait signal to consumer
Jul 16 09:53:07 datanode02 filebeat: 2020-07-16T09:53:07.078+0200#011INFO#011[publisher]#011pipeline/retry.go:225#011  done

Any ideas how to get rid of it? I just cannot keep an eye this log file forever.

Kind regards,
Moritz

I checked the Ingest Pipeline and found the following :

 {
    "remove": {
      "if": "ctx.fortinet?.firewall?.assignip == 'N/A'",
      "field": "fortinet.firewall.assignip"
    }  

So actually these events should not occur since the field actually should be removed beforehand.