Rancher-compose rolling upgrade service with sidekick

Have been trying to perform a rolling upgrade of a service that has a sidekick volume. The error returned is
Bad response statusCode [422]. Status [422 status code 422]. Body: [code=NotUnique, fieldName=name, baseType=error

This seems to be something to do with the volume being in use.

The docker-compose.yml file I’m using looks like this:

version: '2'
services:
  demo:
  demo-new:
    labels:
      io.rancher.container.pull_image: always
      io.rancher.sidekicks: demo-volume
    tty: true
    volumes_from:
    - demo-volume
    image: myimage
    stdin_open: true
    links:
    - demo-2:demo-2

  demo-volume:
    labels:
      io.rancher.container.pull_image: always
      io.rancher.container.hostname_override: container_name
    tty: true
    volumes:
    - /data
    image: myimage-volume
    stdin_open: true
    command: /bin/bash

The command used is:

rancher-compose -p myproject upgrade demo demo-new

Services without sidekicks can be upgraded successfully.