Form Field Custom Input Rerender

export const User = () => {

    const [existingUser, setExistingUser] = React.useState({});

    const handleUserResponse = (result: any) => {
        if (result.data) {
            setExistingUser(result.data[0]);
        }
    };

    const UserEmailInput = (props: FieldRenderProps) => {
      React.useEffect(() => {
          console.log("UserEmailInput Re-Render");
      }, []);

      const [value, setValue] = React.useState<string>('');
      const emailOnBlur = () => {
        fetch(...).then((response: any) => {
          console.log(response);
          setExistingUser(response.data[0]);
        };
      };

      return (
        <FormMaskedTextBox
            {...props}
            onChange={(e: any) => { setValue(e.value); }}
            onBlur={emailOnBlur}
        />
      );
    };

    return (
        <div style={{ marginTop: '5px', marginBottom: '5px' }}>
            <Card>
                //Form component lives in parent component.
                    <Field
                        name={"email"}
                        label={"E-mail:"}
                        component={UserEmailInput}
                        validator={[
                            requiredValidator("E-mail"),
                            lengthValidator("E-mail", 255),
                            regexValidator("E-mail", emailRegex)
                        ]}
                        id="emailID"
                    />
                </CardBody>
            </Card>
        </div>
    );
};