initialvalue wont change

[softmarshmallow]

formBuilderKey.currentState.value wont change, it always returns the provided initial value.

i'm passing formBuilderKey on parent widget to child widget. on child widget, it uses like widget.formBuilderKey. is it not a valid usecase?

parent.dart

Widget build(BuildContext context){

....
          CustomerEditBasicInfoCard(
            initialValue: data.toCustomerProfileBasicInformationSegment(),
            onChange: (c) {},
            formBuilderKey: formBuilderKey,
          ),
....
}


  void submitForm() {
    print("submitting form");
    final valid = formBuilderKey.currentState.validate();
    if (valid) {
      data.profile.lastName = formBuilderKey.currentState.value[CustomerFormKeys.lastName];
      data.profile.firstName = formBuilderKey.currentState.value[CustomerFormKeys.firstName];
      data.profile.phone = formBuilderKey.currentState.value[CustomerFormKeys.phone];
      data.type = formBuilderKey.currentState.value[CustomerFormKeys.type];
      data.profile.industry = formBuilderKey.currentState.value[CustomerFormKeys.lastName];
      print(formBuilderKey.currentState.value);
    }
  }

child.dart (CustomerEditBasicInfoCard)

  Widget _buildBody() {
    return FormBuilder(
        key: widget.formBuilderKey,
        initialValue: {
          CustomerFormKeys.birth: widget.initialValue.birth ?? DateTime.now(),
          CustomerFormKeys.firstName: widget.initialValue.firstName,
          CustomerFormKeys.lastName: widget.initialValue.lastName,
          CustomerFormKeys.phone: widget.initialValue.phoneNumber,
          CustomerFormKeys.type: widget.initialValue.type
        },
        autovalidate: true,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            _buildTemplateSelection(),
            FormBuilderTextField(
              attribute: CustomerFormKeys.firstName,
              decoration: InputDecoration(hintText: "first name"),
              maxLines: 1,
              validators: [
                FormBuilderValidators.required(),
                FormBuilderValidators.maxLength(20),
              ],
            ),
            FormBuilderTextField(
              attribute: CustomerFormKeys.lastName,
              decoration: InputDecoration(hintText: "last name"),
              maxLines: 1,
              validators: [
                FormBuilderValidators.maxLength(20),
              ],
            ),
            FormBuilderTextField(
              attribute: CustomerFormKeys.phone,
              decoration: InputDecoration(hintText: "phone number"),
              validators: [
                FormBuilderValidators.maxLength(30),
                FormBuilderValidators.numeric(),
              ],
            ),
            FormBuilderDateTimePicker(
              attribute: CustomerFormKeys.birth,
              inputType: InputType.date,
              format: DateFormat("yyyy-MM-dd"),
              decoration: InputDecoration(labelText: "birthday"),
            ),
          ],
        ));
  }

[softmarshmallow]

changing _fbKey.currentState.validate()
to _fbKey.currentState.saveAndValidate() worked