When you turn on the function, it is mandatory to fill in the number, 2 fields of the number appear during registration.
If you turn off the field in the planin settings, then the check does not occur.
delta theme.When you turn on the function, it is mandatory to fill in the number, 2 fields of the number appear during registration.
If you turn off the field in the planin settings, then the check does not occur.
delta theme.
How to leave only one field, but for validation to work.

@Ivan
I think you should remove one that is added by theme and let just plugin one to be placed into form.