odd stockfish analysis

i just watched a fascinating game (, and on completion asked stockfish for analysis. among other things, two stood out:

1 - white played 28 Qab7, whereupon stockfish's numbers went from +21 to +9, but did not post a blunder
2 - when i tried to play through the mistakes, stockfish said there were none for either side, even though black had 2 mistakes and a blunder for black (from the analysis)

can someone explain what stockfish is doing? thanks :)

1. a change from +21 to +9 is from won to won, so it is no blunder, not even a mistake.
2. 9...Qxf6 is a mistake.

@tpr, are you saying that, as long as the value remains one-sided (ie, very positive or very negative), that stockfish won't call blunders or mistakes?

You can't post in the forums yet. Play some games!