When running a composite action, you can not access scripts when running in a container. github.action_path is set, but incorrect

When trying to access scripts in a composite action, it fails when you’re using it inside of a container.

When executing the composite action example, everything works as expected:

    - run: ${{ github.action_path }}/goodbye.sh

The composite action can find the goodbye script with the github.action_path.

But when running this inside a container, it will fail.
github.action_path is set, but can’t be accessed.

Example workflow:

on: [push]

jobs:
  hello_world_job:
    runs-on: ubuntu-latest
    container: node:16
    name: A job to say hello
    steps:
      - uses: actions/checkout@v2
      - id: foo
        uses: actions/hello-world-composite-action@v1
        with:
          who-to-greet: 'Mona the Octocat'
      - run: echo random-number ${{ steps.foo.outputs.random-number }}
        shell: bash

Error message:
No such file or directory

Bad documentation and / or runner bug,

env var GITHUB_ACTION_PATH contains the translated path inside the container.

- run: $GITHUB_ACTION_PATH/goodbye.sh
  shell: bash

Also bash on windows errors out, due to backslashs in path if you follow the docs