Unexpected mate pattern


You should submit that for Tactics Trainer.
From Help:
How can I submit some tactical problems to be included?
Most of our problems come from games we have analyzed. However, we would love to see your submissions which we will include if they meet our standards!
All submissions must be in a .pgn file(s) within a .zip file and emailed to: tacticsub@chess.com.
/ A zip file for a .pgn? That must have been written when people were still using dial-up.