bug: vue3.2.29通过v-for显示component组件通过ref调用子组件方法时提示子组件方法为undefined

[zwyao314]

代码：

---

  this.tabs.forEach(tab => {
    let formRef = this.$refs[tab.key];
    if (tab.isForm) {
      let formValidator = formRef.validateForm();  // 该子组件的方法为undefined
    }
  });