[dmurray]

> I guess in this situation the knight against two bishops keeps the draw.

Yes, though - I think I can say without exaggeration - no human on earth can tell you exactly which positions the knight can hold out against the bishops for the required 50 moves.

So it's a strange problem: a perceptive beginner can find the right move through a process of elimination, but even a super-GM can't be certain it's good enough, or defend it accurately against a computer. I don't see anything about that that makes it a particularly good test of an LLM.