devcontainer on Windows mounts empty directory while docker-compose mounts everything correctly

Question

Here are my definitions:

• structure:

.devcontainer
  devcontainer.json
docker
  bot
    Dockerfile
    entrypoint.sh
  docker-compose.base.yaml
  docker-compose.dev.yaml
pdm.lock
...

• devcontainer.json:

{
  "name": "SomeName",
  "dockerComposeFile": [
    "../docker/docker-compose.base.yml",
    "../docker/docker-compose.dev.yml",
  ],
  "service": "bot",
  "shutdownAction": "stopCompose",
  "workspaceFolder": "/mounted",
}

• docker-compose.base.yaml (the dev one is currently just empty services: {}):

version: '3.9'

services:
  bot:
    build:
      context: ..
      dockerfile: docker/bot/Dockerfile
    volumes:
      - '../:/mounted'
    restart: unless-stopped

• Dockerfile:

FROM python:3.11.5

WORKDIR /mounted

ENV PIP_ROOT_USER_ACTION ignore
ENV PYTHONUNBUFFERED 1

RUN apt-get update && apt-get install -y --no-install-recommends \
  nano \
  vim \
  grc \
  git \
  htop \
  iptraf \
  && apt-get purge -y --auto-remove \
  && apt-get clean \
  && rm -fr /var/lib/apt/lists/* /tmp/* /var/tmp/*

RUN pip install -U pip pdm && pdm sync

COPY docker/bot/entrypoint.sh /usr/local/bin/
RUN chmod a+x /usr/local/bin/entrypoint.sh

ENTRYPOINT ["entrypoint.sh"]

The build of the container fails on pdm sync command, which requires pdm.lock to be mounted and present. And it is mounted normally when using docker-compose up directly.

When I added directory listing:

RUN pip install -U pip pdm && ls -a && pdm sync

that reported only . and .. as options, so /mounted is empty.

Why is the volume not mounted correctly? What can I do to fix it?