Yeah, the non-disclosure is most telling IMO. 11bit is an experienced development studio, it is not credible for them to not know about Steam's AI disclosure requirement.
Thus, to me, there are three possible explanations: They either decided to hide the use of genAI because they were aware that disclosing its use would hurt their reputation. Or they decided that it was "no big deal" and were willing to risk gambling with their reputation and their relationship with Valve. Or they will blame this on outsourcing and freelance contractors, which they then failed to supervise and/or instruct properly.
Either option makes them look bad and extremely sloppy at best.
I am relieved.