And some people are too kind for their own good. Tell his homeless ass he can follow rules or pitch a tent somewhere.

Obviously the lawyer who asked the AI to generate the subpoena would be responsible for the malpractice, there is no mechanism at all to shift that liability to the AI provider. The lawyer who let's AI fuck up on behalf of a client could be sued by the client or punished by their state bar / disciplinary committee even if the Client signed a waiver about this in the retainer.

The only thing a bit perverted about what you described was your own reaction, but go on and keep telling on yourself.