vendor.js hash value changes after component modification

Reproduction link

https://github.com/iCodeBIT/vendorHashTest

Steps to reproduce

1. Delete a .vue file in /src/components directory, like Hello2.vue.
2. npm run build;
3. After building, we can see from "git status" that a new vendor.js is generated.

What is expected?

The hash value of vendorjs should NOT change.

What is actually happening?

The hash value of vendorjs has changed.

The project is generated from vue-template/webpack. In my point of view, vendorjs is extracted from node_modules, modifications in /src/components should not affect vendorjs. Is there anything wrong with the webpack config?