Logstash netflow codec says "no template has been received" but it did receive one

Hello, the Logstash codec logstash-codec-netflow says it can't decode a flowset because no template has been received. When looking in the packet capture, a template has been sent.

[2024-02-02T13:10:19,136][WARN ][logstash.codecs.netflow  ][main][bb95707be2d808262891c02debd1c7486b2a28cbba83f5acb495ce1bac18e7eb] Can't (yet) decode flowset id 257 from observation domain id 1, because no template to decode it with has been received. This message will usually go away after 1 minute.
[2024-02-02T13:10:19,136][WARN ][logstash.codecs.netflow  ][main][bb95707be2d808262891c02debd1c7486b2a28cbba83f5acb495ce1bac18e7eb] Can't (yet) decode flowset id 256 from observation domain id 1, because no template to decode it with has been received. This message will usually go away after 1 minute.
[2024-02-02T13:10:19,140][WARN ][logstash.codecs.netflow  ][main][bb95707be2d808262891c02debd1c7486b2a28cbba83f5acb495ce1bac18e7eb] Can't (yet) decode flowset id 258 from observation domain id 1, because no template to decode it with has been received. This message will usually go away after 1 minute.

Logstash version: 8.11.4

Configuration

input {
  udp {
    port  => 2055
    codec => netflow {
      cache_save_path => "/tmp"
    }
  }
}
output {
  stdout{}
}

In the template cache there is in fact no template with those numbers

# cat /tmp/ipfix_templates.cache |  jq '. |= keys'
[
  "1|259",
  "1|261",
  "1|262",
  "1|273",
  "1|274"
]

But in the PCAP a template is transmitted regularly

Cisco NetFlow/IPFIX
    Version: 10
    Length: 104
    Timestamp: Jan 25, 2024 11:05:29.000000000 W. Europe Standard Time
    FlowSequence: 224
    Observation Domain Id: 1
    Set 1 [id=3] (Options Template): 259,257,256,258
        FlowSet Id: Options Template (V10 [IPFIX]) (3)
        FlowSet Length: 88
        Options Template (Id = 259) (Scope Count = 1; Data Count = 7)
        Options Template (Id = 257) (Scope Count = 1; Data Count = 1)
        Options Template (Id = 256) (Scope Count = 1; Data Count = 1)
        Options Template (Id = 258) (Scope Count = 1; Data Count = 1)

It looks like a bug.

Any idea ?

It looks like PR is still opened