Host user dependent service create fail

I’m running “docker stack deploy -c docker-compose.yml elk” as the docker user (a member of the docker group) to deploy a stack. One of the services in the stack fails to deploy. “docker service ps” yields this error:

invalid mount config for type “bind”: bind source path does not exist

The error is due to the following portion of the compose file:

volumes:
  - ./configs/logstash:/usr/share/logstash/pipeline:ro

The source directory definitely exists and is in the same directory as the composer file.

When I run the stack deploy command as the root user, using the same composer file, it works fine with no error. I’m using Docker 17.06 on a CentOS 7.2 host.

This link suggests that the deploy should work when running as a user that’s a member of the docker group. Is this a bug?