This is a bug in njamd, not ElectricFence, but there's no njamd category in bugzilla, so I'm using the closest one. You should probably get the bugzilla maintainers to add an njamd category. When you make a typo in the njamd curses interface, backspace over it and hit return, the interface doesn't understand the command you typed.
assigned to jakub
seems to be working in the 7.0 release, and in my current development release stuff.