workflow level env. is unrecognised on job level's 'if'-expression when calling reusable workflow

the idea is to have a workflow_dispatch input to choose wether or not to execute tests after the build part is done.

Describe the bug
environment variable defined on workflow level is not available for if-condition on job level - in case the job is calling another "reusable" workflow.
everything is fine within a regular job and it's steps.

To Reproduce
Example:

name: ay_test_condition

on:
  workflow_dispatch:
    inputs:
      build_skip:
        description: 'skip maven and chart builder'
        required: true
        default: false
        type: boolean  
      test_skip:
        description: 'skip product integration tests'
        required: true
        default: false
        type: boolean    

# workflow level env
env:
  BUILD_SKIP: ${{ github.event.inputs.build_skip == 'true' }}
  TEST_SKIP: ${{ github.event.inputs.test_skip == 'true' }} 

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
      - name: Display build environment
        id: displayBuildEnv
        shell: bash
        run: |
          echo "build_skip: ${{ github.event.inputs.build_skip }}";
          echo "env.BUILD_SKIP: ${{ env.BUILD_SKIP }}";
          echo "test_skip : ${{ github.event.inputs.test_skip }}";
          echo "env.TEST_SKIP: ${{ env.TEST_SKIP }}";
      
      - name: build something
# works fine here (at workflow.job.step level)      
        if: ${{ env.BUILD_SKIP == 'false' }}
        run: |
          echo "Building something"   

  test:
    needs: build
# does not work here (at workflow.job-workflow_caller)    
    if: ${{ env.TEST_SKIP == 'false' }}
    uses: ./.github/workflows/ay_test-workflow2.yml
    with:
      teststatus: true   

Expected behavior
the env should be available everywhere, since it's declared on workflow level.

Runner Version and Platform

Current runner version: '2.287.1'
Operating System
Ubuntu
20.04.3
LTS
Virtual Environment
Environment: ubuntu-20.04
Version: 20220131.1
Virtual Environment Provisioner
1.0.0.0-main-20220201-1

What's not working?

Errormessage:

The workflow is not valid. .github/workflows/ay_test_condition.yml (Line: 45, Col: 9): Unrecognized named-value: 'env'. Located at position 1 within expression: env.TEST_SKIP == 'false'