webpack5 cache not working as expected

[willson-wang]

Using [email protected] version, this is a reproduction demo
Step 1: git clone demo
Step 2: yarn install
Step 3: Modify infrastructureLogging in node_modules/@vercel/ncc/dist/ncc/index.js.cache.js: {debug: /webpack.cache/} to print the webpack cache log
Step 4: yarn build executes the first build
Step 5: Without making any file changes, yarn build executes the second build
Step 6: Without making any file changes, yarn build executes the third build

You will find that after the second time, the build cache will change every time. You can see from the cache log [but build dependencies have changed.]

The expected result is that webpack5 cache can work as expected, and the cache will not be reused every time it is built.