Stockfish bug?

In my Sicilian defence study, I was putting a variation into the analysis board and when I entered a certain move, it said mate in 0! The variant was standard and everything else seems to be working properly. Here's the link: lichess.org/study/NaoiObC1/xcQBNMI9
Anyone got any ideas?

It's after move 9.Bc4.

The ghost of bobby fischer inside of stockfish. *whispers* sac sac mate...