Why can't the engine understand that move is checkmate, every time I put it in game review it recommends Qg4. I know that they are put checkmate but I'm curious as of why Qg5 is showing warning. Maybe I have to upgrade Stockfish. I am not really sure.
I think that's a glitch that's been going on for a bit. Sometimes a checkmate will be mistakenly evaluated as as a blunder, especially if the queen is right next to the enemy king.