null version when using conventional commits and independent versions

Expected Behavior

Each package will have a new package version correctly set based on the conventional commit history and previous package versions

Current Behavior

All package versions are set to null when using conventional commits

Steps to Reproduce (for bugs)

1. Set up a project with conventional commits and independent package versioning
2. Use the Lerna configuration below
3. Create some packages
4. Update the package versions by running npx lerna version
5. The changelogs and tags should be created for all packages, but the version number is null

{
  "command": {
    "publish": {
      "bump": "from-git",
      "registry": "https://npm.pkg.github.com",
      "yes": true,
      "verifyAccess": false
    },
    "version": {
      "conventionalCommits": true,
      "ignoreChanges": [
        "package.json",
        "package-lock.json",
        "**/*.md"
      ],
      "message": "chore(release): update package versions",
      "private": false,
      "push": false
    }
  },
  "packages": [
    "packages/*"
  ],
  "version": "independent"
}

Context

I have a project with multiple utility packages, which have independent versions. The project uses conventional commits and independent package versioning. Initially I was able to get around the issue by manually setting a releave version (e.g. lerna version 1.0.0), but now that the package versions are starting to diverge I can no longer do this as it will apply the same version to all packages.

Your Environment

Start by reproducing the issue with the provided lerna.json and npx lerna version, using the listed Node and Lerna versions. Trace the conventional-commit and independent-version calculation from that entry point. Done means each package receives a non-null version based on its commit history and previous version.