Yep. I actually mention that specific question in the article as an unsolvable question for machine learning, at least given our current constraints.

Those are generally rare questions though because difficult questions for bots are also difficult questions for humans. HQ can't have too many of those questions without degrading the player experience.

Because of that, I don't think we will ever get beyond 10/11 questions right per game. That still leads to a decent chance at winning at least one game per week though.