### Version 3.2.22 ### Reproduction link [github.com](https://github.com/TwT-L/async-component-test) ### Steps to reproduce 点击「Goto CheckBox」 然后再点击「back」。 重复上述步骤 ### What is expected? 第二次点击「back」仍然能返回「TextBox」 ### What is actually happening? 无法返回「TextBox」,ref 指向的component变成了`null` <!-- generated by vue-issues. DO NOT REMOVE -->