On move 14 computer says: "f4? mistake. better was Nd5" if you follow the line suggested you will see that black has a mate in 2 after the end of the analysis...it' s not the first time i find strange comments in computer analysis and since it s the primary reason for wich i am a member of the site, i would want understand. thank' s for the attention

sorry i see now that white can play Nb4 and there is no mate but after ...a5, white is losing a piece. so the problem perist