The endgame which busted chess engines

I just played a match where my opponent managed to find a draw in a knight vs bishop endgame being down 2 connected passers! Great defensive positioning by him, making it impossible for me to put him in zugzwang and advance my g pawn. I tried some tricks but all he had to do was keep moving his knight back and forth and i could do nothing to break the blockade. The funny thing is that after the match i ran some computer analysis, and chess.com engine gives an insane -5 evaluation for this position, and only sees that it's a dead draw after 50 waiting moves! This position also made my local stockfish go nuts, giving a -3 evaluation. Kudos to my opponent, i missed some nice moves on time pressure but he also defended very well, and even got a very scary attack against my king in the middle game after sacrificing the light square bishop

Blacks king controls 6 squares to whites 4

Blacks bishop controls 9 squares to the knights 5

Black has an extra pawn

This is why you do not just blindly believe what an engine says.  And why you dont use an engine for endgames.  

Yeah, after the game i ran the analysis to see if i missed a forced win, and it was sad to see a -5 evaluation and still no way to break through xD

I was pretty sure he was dead after move 53, because if he captured on g4 my passer would promote, and if he captured on h3 it was also an obvious win. But that blockade was genius.

I thought after capturing his last pawn i would be able to somehow put him in zugzwang and advance my g pawn, sacrificing the h pawn but getting a queen, or capture his knight, but yeah it obviously failed

Your wrong move was on move 53. You could have gone to capture white's passer. A rule in positions with connected passers and minor pieces is: Control the squares in front of the pawns before pushing them.

Well sometimes engines are like that. The -5 evaluation came about probably due to material considerations. If the computer is able to see a draw immediately (like a perpetual or something) the evaluation will most likely be 0.00 (+ or - 0.1 at most). In a situation where the opponent king will be chased around the board but a win cannot be forced with best play from both sides, the computer may register the evaluation as 0.00 since it is unable to see many moves deep. I had an over the board friendly game several months back which the evaluation remained +0.72 for very long. Finally the computer acknowledged that there was no clear way to force a win after chasing my king around, but at the time I was like, why doesn't it just say 0.00? A pity it is like that sometimes.