If you run across on like that you can just the Help option in the menu when in the puzzle page to report a Bug. That will capture the page and you can add information about it.
I have reported this specific one to staff.
Mistake in 3131 rated puzzle!
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Link to the puzzle!: https://www.chess.com/puzzles/problem/2594308
There were 2 correct answers to refute against Bb5+ for black to win. One was Kd8, and the other was Nc6!!. It's not the best move, but a good move that also works.
I play Nc6 in the puzzle, but said it was wrong, but when I checked the evaluation, it said -3, indicating a winning position, so no, Nc6 is not incorrect. Kd8 is a bit better (-4), but Nc6 works.
Why? White cannot take the knight by the pawn, and if you take with the bishop, it gets even worse, with both the rook and pawn being under attack.
The only thing white can play is a king move to connect the rook to the queen, or else it gets gobbled by the black queen. Kf1 is a forced mate, so Kd2 is probably better.
Although it appears good for white, after O-O!! Black is completely winning. White, still cannot take the knight, with Rad8+! being met. White can't do anything to stop Nd4! attacking both bishops and will eventually be up in material. If white protects the bishop, then black will either force checkmate white, or win the white queen. (these calculations gave me a headache, because engines are too sigma alpha these days)
The "correct" option is more easy and obvious than the 2nd possible, but the 2nd option is not wrong! Hence, the puzzle has a mistake with two correct moves for black.