Wrong user. PHP can't write to ./storage

[vardumper]

Description

I noticed that on Ubuntu, the user is not correctly set to appuser:appgroup
My custom Dockerfie looks like this.

FROM ghcr.io/craftcms/image:8.4

USER root

COPY .docker/local/craft/${nginx_config} /etc/nginx/nginx.conf
COPY .docker/local/craft/supervisord.conf/nginx.ini /etc/supervisord.d/nginx.ini

# set the sockets and pid files to be writable by the appuser
RUN mkdir -p /var/log/nginx && chown -R appuser:appgroup /var/log/nginx
RUN chown -R appuser:appgroup /var/lib/nginx && touch /run/nginx.pid && chown -R appuser:appgroup /run/nginx.pid

# make sure pg_dump (17) is available
RUN curl -fsSL https://www.postgresql.org/media/keys/ACCC4CF8.asc|gpg --dearmor --yes -o /etc/apt/trusted.gpg.d/postgresql.gpg && \
    echo "deb http://apt.postgresql.org/pub/repos/apt/ `lsb_release -cs`-pgdg main" |tee  /etc/apt/sources.list.d/pgdg.list
RUN ["apt-get", "update", "--allow-releaseinfo-change"]
RUN ["apt-get", "install", "-y", "zsh", "nano", "postgresql-client-17", "composer"]

COPY --chown=appuser:appgroup . .

USER appuser

On macOS this works smoothly. Not so on Ubuntu. All files/dirs have ubuntu as the user:group

Additional info

• Craft version: 4.x
• PHP version: 8.4
• Database driver & version: PG 17
• Plugins & versions:

Fix

docker compose exec -it -u root web zsh and cd /app && chown -R appuser:appgroup . Fixed this.

I am guessing my COPY statement is wrong?!