Automate underpromotes, the draws in Bishop and Kinght endgame

I recently played an Automate game https://www.chess.com/automate/989591 . My opponent got an endgame with a Knight and a pawn versus my lone King. However, the game decided to unterpromote the pawn to a bishop and the failed to mate with knight and bishop. I know that the automate games are controlled by Stockfish at a low depth, so I understand why it failed to get the mate, but I do not understand why it underpromoted in the first place. There was no risk of stalemate, so promoting to a queen should have been best not matter at what depth Stockfish was running. Can someone enlighten me why that happened?

trollfish straight trolling

All the more hilarious since there are forced mates in just 7 moves if promotes to a queen