There's very little reason to believe Irregular was involved in that incident, and the article presents no evidence to that effect. So it's "There's not a teapot orbiting the sun somewhere between Earth and Mars (as far as we know)."

We know for certain. The involvement of Irregular in the other cases was never a secret, they were quite open about what they were working on and the results of the evaluations were being published on their website.

Their disclosures in other cases is not evidence of non-involvement in this case.

Can you explain in what way you think they could possibly have been covertly involved?

OpenAI explicitly stated those were separate incidents: https://openai.com/index/third-party-cyber-evaluations-invol...

If you want to believe without evidence why bother to read articles? Faith doesn’t require that, but if you’re serious then a lack of evidence is important.