How to use vuelidate on nested structure data?

Question

import useVuelidate from '@vuelidate/core';
import {helpers, required} from '@vuelidate/validators';

const state = reactive({
  list: [
    {
      first: {
        regex: 'test',
        type: ''
      },
      second: {
        regex: null,
        count: 0
      }
    },
    {
      first: {
        regex: '',
        type: 'test'
      },
      second: {
        regex: null,
        count: 0
      }
    }
  ]
});
const rules = {
  list: {
    $each: helpers.forEach({
      first: {
        regex: {
          required
        },
        type: {
          required
        }
      },
      second: {
        regex: {
          required
        },
        count: {
          required
        }
      }
    }),
  },
};
const v$ = useVuelidate(rules, state);

and when I print {{ v$.list.$each.$response }}, the result is

TypeError: validatorFunction.call is not a function
    at Object.entries.reduce.$valid (index.mjs:105:49)
    at Array.reduce (<anonymous>)
    at Object.entries.reduce.$valid (index.mjs:102:66)
    at Array.reduce (<anonymous>)
    at unref.reduce.$valid (index.mjs:99:70)
    at Proxy.reduce (<anonymous>)
    at Proxy.$validator (index.mjs:98:32)
    at callRule (index.mjs:90:15)
    at ReactiveEffect.fn (index.mjs:162:22)
    at ReactiveEffect.run (reactivity.esm-bundler.js:178:19)

So I can't access v$.list.$each.$response.$errors[index].first.regex.length

Help please.

I checked 'https://vuelidate-next.netlify.app/advanced_usage.html#using-the-new-foreach-helper' but it works on 1depth structure object. e.g. const state = reactive({list: [{name: 'test'}, {name: 'test2'}]}); in my case, 2depth or higher depth structrue object did not work correctly.