Stockfish level 6 doesn't know how to checkmate with a queen against a b-pawn

So from move 68 onward, White had a huge advantage and I (as an anonymous with the black pieces) was already expecting to get checkmated. I was very surprised when it played the later moves like a beginner, although its level (and strength) was about 2300. I even was almost laughing when the game was over.
How can anyone, even the computer play like this?? Is it a bug or what??

that is odd

My guess is that it is programmed to not always play the top moves, and for this particular endgame, any move that isn't the top move will probably lose progress. So maybe it starts to make progress, but then thinks, "oh wait, I'm playing too well, time to make a mistake", and then loses progress, then starts to make progress again, but not enough before its time for another mistake. Or something like that.

No big deal. These are merely AI levels (and not real strength of engine) that are programmed to blunder every n moves or so. Playing these levels is bad if one really wants to improve. Age old topic since long time!

@Akbar2thegreat said in #4:
> Age old topic since long time!
Hey guy, prove it. Show me where and how it is age old. And, from the next time, please learn how to speak politely here.
> No big deal. These are merely AI levels (and not real strength of engine)
It's (almost) real strength for a 2300. I already have mentioned it in the beginning.

@SwApNeEl1 said in #5:
> Hey guy, prove it. Show me where and how it is age old. And, from the next time, please learn how to speak politely here.
I am tired of people making threads which all have same essence in reality and hence the case. I don't
Search in forums and you will find countless threads where people boast that they defeated SF level 8 or something related like that. But defeating SF level 8 is not big deal either. These are merely AI levels not as strong as Stockfish would at different depths. There's difference. And these AI levels are programmed to blunder at times unlike the ones if you download from official Stockfish website of particular engine like 6 which was released in 2014. I am not expert in these 'things' (but know quite about it) so better ask any user who is developer or who knows well about these things like Toadofsky, TBest, benwerner, FishyVishy, etc.
> It's (almost) real strength for a 2300. I already have mentioned it in the beginning.
Nah, just told you entire story or best is to download SF 6 from stockfish.org and then compare it with AI level 6 here and surely you will get the answer.

Programmed mistakes are good in full games, because then the style of computer becomes more human.
However, such computer is useless in training some elementary endgames. To obtain relatively best
result it is good to train elementary endgames with Stockfish level 8 (at this level Stockfish can win the position
presented in #1).

@SwApNeEl1 said in #1:
>
Then make your own AI level!
If I remember correctly, a dev on a thread before has said that there's vast difference between AI levels (these are different on platform like Lichess, chess.com,etc and Stockfish strength of particular version.

This seems to be a common issue with bots. If I'm remembering correctly, one of the higher level chess.com bots couldn't mate with two bishops. The bots don't seem to know the strategy for the tough checkmates.

Oh, stop it, I was merely pointing out that Stockfish 6 could not checkmate me in a simple queen ending.
Thats the end of it.
And, by the way, @Akbar2thegreat ur URL is wrong. It should have been stockfishchess.org/