The engine recognizing it as just a mistake is likely because of the enormous advantage you already have, so losing a queen would have made little difference in the result of the game, therefore making it a mistake. In other words, blunders are usually game-changing or gives the other person chances, and mistakes usually lower your chances of winning but aren't game-defining moments
When you stupidly blunder your queen on move 18 for completely no reason and it's just a mistake
@1
"I get two rooks, a knight, and multiple pawns up, then proceed to blounder my queen"
++ That is neither a blunder, nor a mistake: it wins just the same.
There are no bonus points for a faster win or for a win with more material up.

@1
"I get two rooks, a knight, and multiple pawns up, then proceed to blounder my queen"
++ That is neither a blunder, nor a mistake: it wins just the same.
There are no bonus points for a faster win or for a win with more material up.
It still is a blunder, as I am losing 9 points of material completely by accudent, but it isn't classified as a blunder because of my significant advantage.

It still is a blunder, as I am losing 9 points of material completely by accudent, but it isn't classified as a blunder because of my significant advantage.
I agree with you! It may not have affected the outcome, but you know it was a blunder because it was an oversight.....a mistake. And you want to at least take away a lesson so that's it's less likely to happen again. If you just accept it as ok, then there's no reason to learn anything from it.
So I get two rooks, a knight, and multiple pawns up, then proceed to blounder my queen because my brain shorted out and I thought the rook was still guarding for some reason, and chess.com's like nO thAt'S juSt a MisTaKe
And then I won
https://www.chess.com/game/live/59813966403