Beating a promoted queen gives a queen instead of a pawn

Crazyhouse
In an analysis i beat a rook on a8 with a pawn on b7 promoting to a queen.
Then Qxa8 from black gives black a queen instead of a pawn in the bag.
The program shows a queen in the bag, but counted it not as a true queen,
because a mate in one with putting this queen on the board wasnt recognized from the analysis program,
because it suggested a move that does not prevent the mate.
As i put the queen with black on the mating square, he recognized it as mate and the game was over.

It was a crazyhouse game.

That's how it works.

It's a bug.