I was just curious, nothing more. I was asking myself how hard is it to checkmate with 3 knights so I fired up Stockfish (without any tablebase) and was shockingly surprised to see the search results bump up and down showing different « distance-to-mate » ! How can a search at 41 plies deep jump from 43-35-36-28-25-33 plies to mate?!?!? Does anyone have an answer?
So I’m wondering why Stockfish, at 41 plies deep, is not able to stick to a mate-in-33 principal variation all along starting from ply 33 ?