Button problem in return to Cheesetroid

My girls are in return to Cheesetroid and have been trying to build the button on the mini breadboard. the wiring is correct all the other buttons are working red,green, yellow, blue. I have swapped wired out with ones we knew work I have swapped out breadboards we knew worked, we have swapped out buttons we knew worked. I have pushed the button three times to detect it and I don’t know anything else to do. Right I’m having them use my teacher model to complete their final challenge but I really like to know how to fix the issue on their bot. Any help is appreciated!
Cheryl

What version ae you running on both Pi’s - go to the Piper main menu and click the GEAR icon. at the bottom left, in small font, you will see the Piper version.

What happens if you disconnect the wires to the switch and touch them together?