No IPv6 allocated when running as Service

Hey,

I wanted to run a Bouncer inside of a Docker swarm.
The issue is, it does not get any IPv6 when running as service, even on the same node.

docker service create --name bouncer --replicas 1 --mount type=bind,src=/swarm/volumes/znc/,dst=/config -p 6501:6501 -e TZ=Europe/London linuxserver/znc

Gives me, when I run: docker inspect nsah9p3os4kt

{
“NetworkID”: “k4trg51uziobqdzl99xs9pmfj”,
“Addr”: “10.255.0.6/16”
}

When I deploy this container not as a Service:

docker run -i -t --name bouncer --mount type=bind,src=/swarm/volumes/znc/,dst=/config -p 6501:6501 -e TZ=Europe/London linuxserver/znc

It returns me when I run docker inspect dc1ecaa3e7a6:

                "Gateway": "172.17.0.1",
                "IPAddress": "172.17.0.2",
                "IPPrefixLen": 16,
                "IPv6Gateway": "2607:5300:203:xxxx:xxxx::1",
                "GlobalIPv6Address": "2607:5300:203:xxxx:xxxx:xxx:ac11:2",

So why does my Container not get IPv6?

Any suggestions?