During the installation of Confluence using the Docker container we are using root permissions:

def gen_cfg(tmpl, target, env, user='root', group='root', mode=0o644, overwrite=True):

As a good practice, we should use non-root user in this case. As we already have confluence user and files are written by it, please change the entrypoint.py to use something like this:

def gen_cfg(tmpl, target, env, user='confluence', group='confluence', mode=0o644, overwrite=True)