Can't bind volume between container and other container (docker-in-docker)

I try to setup my gitlab runner on my M1 MacBook for some environment testing. My CI workflow is quite simple : build -> test -> deploy. I use docker executor and for testing tasks I use docker-compose because I have to deploy a database beside the service I want to test.

My CI works perfectly on a EC2 running Ubuntu. But when I tried to run my runner on macOS, my volume ./backend is not bind with /app. I tried to ls /app on backend container and with the EC2 all files and folders are here but not when I run the runner on macOS.

gitlab-ci.yml (this is just the backend_test part:

test_backend:
  stage: test
  needs: ["build_backend_image"]
  image: docker
  services:
    - docker:dind
  before_script:
    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
    - DOCKER_CONFIG=${DOCKER_CONFIG:-$HOME/.docker}
    - mkdir -p $DOCKER_CONFIG/cli-plugins
    - apk add curl
    - curl -SL https://github.com/docker/compose/releases/download/v2.3.3/docker-compose-linux-x86_64 -o $DOCKER_CONFIG/cli-plugins/docker-compose
    - chmod +x $DOCKER_CONFIG/cli-plugins/docker-compose
  script:
    - docker compose -f docker-compose-ci.yml up -d db
    - docker exec db sh mongo_init.sh
    - docker compose -f docker-compose-ci.yml up -d backend
    - pwd
    - ls
    - ls backend
    - docker exec backend pwd
    - docker exec backend ls -l
    - docker exec backend ls / -l
    - docker exec backend pip3 install --no-cache-dir --upgrade -r requirements-test.txt
    - docker exec backend pytest test --junitxml=report.xml -p no:cacheprovider
  interruptible: true
  artifacts:
    when: always
    reports:
      junit: backend/report.xml
  rules:
    - if: $CI_PIPELINE_SOURCE == 'merge_request_event'
    - if: $CI_COMMIT_BRANCH == 'develop'
    - if: $CI_COMMIT_BRANCH == 'master'

gitlab-runner/config.toml:

concurrent = 2
check_interval = 0

[session_server]
  session_timeout = 1800


[[runners]]
  name = "Macbook"
  url = "https://gitlab.com/"
  token = "xxxxxxxxxx"
  executor = "docker"
  [runners.custom_build_dir]
  [runners.cache]
    [runners.cache.s3]
    [runners.cache.gcs]
    [runners.cache.azure]
  [runners.docker]
    tls_verify = false
    image = "docker:20.10.13"
    privileged = true
    disable_entrypoint_overwrite = false
    oom_kill_disable = false
    disable_cache = false
    volumes = ["/certs/client", "/cache"]
    shm_size = 0

EC2 runner ls output:

$ docker exec backend ls /app -l
total 36
-rw-rw-rw-  1 root root  285 Jun  3 15:30 Dockerfile
-rw-rw-rw-  1 root root  325 May 20 23:49 DockerfileTest
-rw-rw-rw-  1 root root   48 May 20 23:49 __init__.py
drwxrwxrwx 11 root root 4096 Jun  4 17:17 app
-rw-rw-rw-  1 root root 4286 Jun  4 16:41 favicon.ico
-rw-rw-rw-  1 root root   33 Jun  4 16:41 requirements-test.txt
-rw-rw-rw-  1 root root 1673 Jun  4 16:41 requirements.txt
drwxrwxrwx  6 root root 4096 Jun  4 16:41 test

macOS runner ls output:

$ docker exec backend ls /app -l
total 0

docker-compose-ci.yml:

services:
  backend:
    container_name: backend
    image: $CI_REGISTRY_IMAGE/backend:$CI_COMMIT_SHA
    volumes:
      - ./backend:/app
    networks:
      default:
    ports:
      - 8000:8000
      - 587:587
      - 443:443
    depends_on:
      - db

  db:
    container_name: db
    image: mongo
    volumes:
      - ./mongo_init.sh:/mongo_init.sh:ro
    networks:
      default:
    environment:
      MONGO_INITDB_DATABASE: xxxxxxx
      MONGO_INITDB_ROOT_USERNAME: admin
      MONGO_INITDB_ROOT_PASSWORD: admin
    ports:
      - 27017:27017


networks:
  default:
    driver: bridge