Docker Swarm: docker stack deploy fails when executed second time - docker

Question

I have a single node docker swarm which has just been created with docker swarm init.
I have a docker-stack.yml which contains the following deployment:
version: '3.3'
services:
website:
image: docker.pkg.github.com/foo/bar/bar:latest
ports:
- "80:80"
- "443:443"
environment:
HOST: bar.com
secrets:
- site.key
- site.cert
networks:
- foo-net
networks:
foo-net:
driver: overlay
external: true
secrets:
site.key:
external: true
site.cert:
external: true
First, I login into the registry and it tells me that the login was successful.
Second, I deploy the stack
$ docker stack deploy --with-registry-auth --compose-file docker-stack.yml foo
Creating service foo_bar
After that, the service is running and everything works as expected.
However, when I try to deploy a stack with the same command a second time (a few seconds later), it fails with the following message.
$ docker stack deploy --with-registry-auth --compose-file docker-stack.yml foo
Updating service foo_website (id: uvtqpdx74784dy9egj5i1c7sb)
image docker.pkg.github.com/foo/bar/bar:latest could not be accessed on a registry to record
its digest. Each node will access docker.pkg.github.com/foo/bar/bar:latest independently,
possibly leading to different nodes running different
versions of the image
Why does this happen?
All networks and secrets are created beforehand and my docker version is:
$ docker version
Client:
Version: 19.03.6
API version: 1.40
Go version: go1.12.17
Git commit: 369ce74a3c
Built: Fri Feb 28 23:45:43 2020
OS/Arch: linux/amd64
Experimental: false
Server:
Engine:
Version: 19.03.6
API version: 1.40 (minimum version 1.12)
Go version: go1.12.17
Git commit: 369ce74a3c
Built: Wed Feb 19 01:06:16 2020
OS/Arch: linux/amd64
Experimental: false
containerd:
Version: 1.3.3-0ubuntu1~18.04.2
GitCommit:
runc:
Version: spec: 1.0.1-dev
GitCommit:
docker-init:
Version: 0.18.0
GitCommit:
I appreciate any help!
Thanks