When setting up a responsive form for a Nintex Task form, we wanted to include a list and offer choices. But the choice list also gives an option for allowing fill-in choices. The fill-in choices field shows up on the computer version of the form, but not the iPhone version. So, as a fix, we had to add a single line of text field below the choices list to allow users to fill in their own values. I don't know if the developers are even aware that this problems exists. If the functionality states that fill-in choices are allowed, when, in fact they do not on the iPhone version of the form, that is a problem.