This quote from your link is positively scary:

> Some examples we saw when evaluating GPT-5.6 Sol included the model packaging exploits in its intermediate submissions to reveal information about a task’s hidden test suite and, in another task, extracting hidden source code detailing the expected answer.

It rhymes with the behaviour Alibaba saw [0], but that was in training. This is in a (semi) released model.

[0] https://www.forbes.com/sites/boazsobrado/2026/03/11/alibabas...