publishConfig does not overrides after "lerna publish"

Current Behavior

publishConfig does not overrides package.json fields after "lerna publish".

original

{
  "main": "./src/index.ts",
  "publishConfig": {
    "main": "./dist/index.js"
  }
}

uploaded on npm

{
  "main": "./src/index.ts",
  "publishConfig": {
    "main": "./dist/index.js"
  }
}

Expected Behavior

package.json should be overwritten and publishConfig should be removed

{
  "main": "./dist/index.js",
}

Steps to Reproduce

1. add "main" field in publishConfig different with original "main" field.
2. run "lerna publish"
3. install uploaded package on npm, and check its package.json

Failure Logs / Configuration

<!-- Please paste your `lerna.json` here -->

<!-- If you have a `lerna-debug.log` available, please paste it here -->
<!-- Otherwise, feel free to delete this <details> block -->

Environment

System:
OS: macOS 12.1
CPU: (10) arm64 Apple M1 Max
Binaries:
Node: 16.14.0 - /private/var/folders/zr/3tkznhqs6sn26wsynpczk2pxz0g_by/T/xfs-a49a6c75/node
Yarn: 3.2.1 - /private/var/folders/zr/3tkznhqs6sn26wsynpczk2pxz0g_by/T/xfs-a49a6c75/yarn
Utilities:
Git: 2.32.1 - /usr/bin/git

Start with the package.json example and trace the lerna publish entry point to see how publishConfig is handled; the issue also includes an empty lerna.json section and no debug log. Reproduce with the listed three steps, then verify that the published package.json uses the publishConfig main value and omits publishConfig.