Element: [Bug Report] filterable doesn't works as expected and cannot initiate default value while using lazyload

[macarole]

Element UI version

2.12.0

OS/Browsers version

77.0.3865.90 (Official Build) (64-bit)

Vue version

2.6.10

Reproduction Link

https://jsfiddle.net/macarole/930a6hj8/17/

Steps to reproduce

1 include elementui
2.use cascader with multiple lazyload
3.test,and filterable doesn't work

What is Expected?

filterable works

What is actually happening?

filterable doesn't work

[macarole]

经过再三测试发现。如果级联需要的树形数据是一份静态的话，那么一切正常。我所谓的正常是多选，默认值，过滤综合使用的结果。但是如果树形数据是异步加载出来，那么上述功能就有问题了。首先，异步出来的数据默认值无法渲染，无法渲染。。。。然后，过滤功能，只有树形数据上某一个分支被单击到最后一级时，那一级上任意一个节点才可以过滤查询啥的。至于其他没有单击加载到最后一级的树杈过滤查询会一直提醒你查不到数据。
综上所述。异步加载数据的时候，过滤会有问题，默认值会有问题，望有大牛帮忙解决，谢谢

[stale[bot]]

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