Dockerfile user change crashes

[DeanAyalon]

Hi there,
As it currently stands, I use a custom dockerfile to run Verdaccio with a few package installations

My dockerfile switches to root to allow apk add

Afterwards, the container runs as it should, but with the addition of this warning:

(node:8) Warning: Verdaccio doesn't need superuser privileges. don't run it under root
(Use node --trace-warnings ... to show where the warning was created)

And so, as written within the Verdaccio documentation, I have modified my dockerfile like so:

FROM verdaccio/verdaccio
EXPOSE 4873

# Get curl for healthcheck script
USER root
RUN apk update && apk add curl

# Copy files into container
COPY --chown=$VERDACCIO_USER_UID:root files/conf/config.yaml /verdaccio/conf/config.yaml
COPY --chown=$VERDACCIO_USER_UID:root files/scripts/* /verdaccio/scripts/

# Script execution permissions
RUN chmod u+x /verdaccio/scripts/*

# Added this, in case the verdaccio user crashes due to having no access to the verdaccio dir
## It did not solve the problem
RUN chown $VERDACCIO_USER_UID:root -R /verdaccio

# When this step is enabled, the container immediately exits with code 2, no logs, no errors
# USER $VERDACCIO_USER_UID
# This step is to avoid the root privileges warning - Verdaccio runs perfectly without it

HEALTHCHECK --interval=10s --timeout=3s \
    CMD /verdaccio/scripts/healthcheck.sh

As stated within the dockerfile comments, if I add the USER verdaccio or USER $VERDACCIO_USER_UID, the container crashes immediately

Docker logs are empty
Docker inspect shows exit code 2, no error message

What am I doing wrong?
Thank you

[DeanAyalon]

Without the USER verdaccio step, I tried entering the container and executing su verdaccio, and I get the following error: This account is not available