I had this problem but pretty sure i found a workaround.
Lets say i wanted to bind the ON/OFF toggle switch to the parking brake:
Bind both the 'Parking Brake On' and also the 'Parking Brake Off' to the same switch (instead of using 'Toggle Parking Brake').
From there, I changed the action type - one being 'ON PRESS' and the other being 'ON RELEASE'
this has seemed to worked for me. not sure about you. hope this helps
Cheers
Sam