I'm guessing it's the shell in the left? If you have the manual refer to pg 53 lamp matrix. It looks like shell #1, bonus chance (cherries), and shoot again are in same column. Shoot again is also in the same row as castle 1.
Check the wiring on the lamps to start.
Or you could try swapping the driver board from one of your other system 3's to determine if it's the board.