Switching to a nested route is automatically running the last commit event from parent's store

Version

3.1.0

Reproduction link

https://codesandbox.io/s/vue-template-c2gtb

Steps to reproduce

1. Open https://codesandbox.io/s/vue-template-c2gtb
2. Click on 'Go to Page with nested router' link
3. Click on 'commit event', it will show an alert box
4. Now change the nested route by clicking 'change nested route to reporting'

What is expected?

Route changed to reporting without showing the 'hello' alert box.

What is actually happening?

Its showing the 'hello' alert box again.

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One of the releated issues https://github.com/vuejs/vuex/issues/1570