ElementUI 树节点点击后，子节点选中但复选框未打勾如何解决？

<template>
  <el-table
    v-loading="loading"
    :data="customList"
    @selection-change="handleSelectionChange"
    :row-key='rowKeyFunc'
    :tree-props="{children: 'children'}"
    :row-class-name="rowClassNameFun"
    ref="table"
    @select-all="selectAllFun"
    @select="selectFun"
  >
    <el-table-column type="selection" width="55" align="center"/>
    <el-table-column label="买家名称" align="center" prop="customName" width="120px"/>
    <el-table-column
      label="联系人"
      align="center"
      prop="linkman"
      width="180"
    >
    </el-table-column>
    <el-table-column
      label="联系电话"
      align="center"
      width="200"
      prop="phone"
    />
    <el-table-column
      label="地址"
      align="center"
      width="200"
      prop="address"
    />
  </el-table>
</template>

<script>
import { getCustomList } from '@/api/iam'

export default {
  data() {
    return {
      // ...
      selectItem: [], // 选中的数据
    }
  },
  methods: {
    // ...
    // 全选或全不选
    selectAllFun(selection) {
      let isAllSelect = this.checkIsAllSelect()
      if (isAllSelect) {
        this.selectItem = []
      } else {
        this.customList.forEach((item) => {
          this.selectItem.push(item)
          if (item.children?.length > 0) {
            item.children.forEach(obj => {
              this.selectItem.push(obj)
            })
          }
        })
      }

      this.customList.forEach((item) => {
        item.isSelect = isAllSelect
        this.$refs.table.toggleRowSelection(item, !isAllSelect)
        this.selectFun(selection, item, true)
      })
    },
    // 选中一行
    selectFun(selection, row, state) {
      this.setRowIsSelect(row, state)
      this.setSelectItem(row)
    },
    // 设置选中状态
    setRowIsSelect(row, state) {
      // ...

      if (!state) this.setSelectItem(row)
    },
    // 设置选中集合
    setSelectItem(row) {
      let index = this.selectItem.indexOf(row)
      if (row.isSelect) {
        // ...
      } else {
        // ...
      }
    },
    // ...
  },
}
</script>