chromatic-cli: GitHub action failing with "Storybook package not installed"

With the release of Chromatic CLI v6.0.0 all our GitHub actions using the chromaui/action@v1 are now failing with the following error:

Chromatic CLI v6.0.0
https://www.chromatic.com/docs/cli

Authenticating with Chromatic
    → Connecting to https://index.chromatic.com
Could not retrieve package info from registry; skipping update check
Authenticated with Chromatic
    → Using project token '*'
Retrieving git information
Retrieved git information
    → Commit '*******' on branch 'main'; found 2 parent commits
Collecting Storybook metadata
    → ✖ Storybook package not installed
Could not find @storybook/react in node_modules.
Most likely, you forgot to run npm install or yarn before running Chromatic.

✖ Failed to collect Storybook metadata
✖ Storybook package not installed
Could not find @storybook/react in node_modules.
Most likely, you forgot to run npm install or yarn before running Chromatic.
→ View the full stacktrace below

If you need help, please chat with us at https://www.chromatic.com/docs/cli for the fastest response.
You can also email the team at support@chromatic.com if chat is not an option.

Please provide us with the above CLI output and the following info:
{
  "timestamp": "2021-09-30T13:35:28.504Z",
  "sessionId": "102360cb-5060-471a-82bd-1600fb5a5512",
  "gitVersion": "2.33.0",
  "nodePlatform": "linux",
  "nodeVersion": "12.13.1",
  "packageName": "chromatic",
  "packageVersion": "6.0.0",
  "flags": {
    "projectToken": "***",
    "workingDir": "packages/console-frontend",
    "fromCI": true,
    "interactive": false,
    "exitZeroOnChanges": true,
    "exitOnceUploaded": true,
    "allowConsoleErrors": false
  },
  "buildScript": "build-storybook -s public",
  "errorType": "Error",
  "errorMessage": "✖ Failed to collect Storybook metadata"
}

This is happening across all our builds now with no code changes to the action/package.json/or lock file in our code so appears to be completely isolated to the action itself.