Spoiler
47...b4 wins the queen. It has nowhere to run.
https://www.chess.com/analysis/game/live/111604362507?tab=analysis&move=91
It was a speed chess game that I watched live. White had plenty of time but he got impatient and missed it. I totally missed it too. The eval bar showed white with a huge advantage but I was mystified. I was looking in the wrong place - on the upper right side of the board. I forgot all about the b pawn. And they were playing so quickly I had brand-new other things to try to figure out.
The game was sharp. That's a chess term that I define as pretty damn complicated and tricky. Trying to understand the positions in real time made my head hurt.
I saw the Queen trap but assumed there was a mate.