Hello Massimiliano
I have commented out this CSS from your custom.css file. Please check the radio button now.
.form-builder-checkbox-item input:checked + label::before, .form-builder-radio-item input:checked + label::before, .sppb-addon-form-builder .sppb-form-check-input:checked + label::before {
background: transparent;
}
.form-builder-checkbox-item label::before, .form-builder-radio-item label::before, .sppb-addon-form-builder .sppb-form-check-label::before {
border: 2px solid #fff;
}
The email field acts like this. You start typing and it starts checking the requirement. This is default HTML input type email behavior. I do not have any idea on how to change it.
Best regards