Logstash cannot assign correct date to log timestamp

Elastic Stack Logstash
7

This is complete filter section:

filter {
  grok {
    match => {"message" => "(?<logTime>[0-9]{2}:[0-9]{2}:[0-9]{2},[0-9]{3})"}
  }
  ruby {
    code => 'event.set("logTimestamp", Time.now.strftime('%Y-%m-%d') + ' ' + event.get("logTime"))'
  }
  date {
    match => ["logTimestamp", "YYYY-MM-dd HH:mm:ss,SSS"]
    timezone => "America/Chicago"
  }
}

And Logstash complains about this part('%Y-%m-%d')

I cannot find any examples in docs, not sure what could be wrong with syntax.