How i?? it's a draw bug !!! https://lichess.org/ZMcEfn4J13Zw

Black can still get mated in this position if he traps himself behind his own pieces. Of course, that would be incredibly unlikely, but it's possible.

Black lost on time. Acoording to the FIDE Laws of Chess it is only a draw if no series of legal moves exists that leads to checkmate.
Here such a series exists:

Hence black lawfully lost.
To avoid such situation: play with increment.