tetragon host_ns namespace selector is leaking some host related events

What happened?

Hello! I am trying to remove host-related events from my tracing policies deployed in a Kubernetes environment with Containerd as a runtime. I use the following namespace selector for this:

- matchNamespaces:
  - namespace: Pid
    operator: NotIn
    values:
    - "host_ns"

So, I expect that I will stop receiving host pid namespace-related events. However, for some reason, I am still receiving some of them (see the file for the exact content).

tetragon_events.json

Moreover, they are all marked with the is_host: true attribute.

Tetragon Version

1.1.2

Kernel Version

Tested on LTS kernels with different distributions:

5.10.0-33-amd64 #1 SMP Debian 5.10.226-1 (2024-10-03) x86_64 GNU/Linux
6.1.0-31-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.128-1 (2025-02-07) x86_64 GNU/Linux
5.4.0-205-generic #225-Ubuntu SMP Fri Jan 10 22:23:35 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
5.15.0-119-generic #129-Ubuntu SMP Fri Aug 2 19:25:20 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux
6.12.0-51.el10.x86_64 #1 SMP PREEMPT_DYNAMIC Fri Feb 7 17:16:47 UTC 2025 x86_64 GNU/Linux
6.6.28-1-debug #astra2+ci96 SMP PREEMPT_DYNAMIC Fri Dec 6 13:12:50 MSK 2024 x86_64 GNU/Linux