Pawn promotion checkmate

I recently won a game by promoting pawn to a queen which was immediate checkmate. I won an award for checkmating with a pawn. Is this a bug or correct?

Bug

I'd say

My grandfather beat me with promotion checkmate the last time I ever played him but I beat a chess tournament organiser first time in exactly the same circumstances but with the roles reversed Great way to learn to win.

my grandfather beat me so I plugged off his life support

No, you should get the "Killer Pawn" achievement by promoting a pawn (or any other pawn move).

I checkmated with pawn promotion because white's king was in a trap by my queen then i was about to promote a pawn

since as soon as it promotes the game ends, when chess.com checks it sees the pawn moving to the square. technically a bug but there is little that could fix it

this also happened to me recently 30 moves into a game but its not that surprising