I have a setup where I have two network cards and two bridges.

br0 is connected to the first network card and br1 is connected to the second
network card.
I am using bridges for VMs. 
In my case, for br1 I do not want any IP addresses since this port is connected
directly to the internet and should be accessed only by a VM.
The problem I am seeing is that even though YaST has br1 configured for No Link
and IP Setup (Bond Ports), it is still obtaining an IPv6 address.
If I configure a port for no IPv6 then it should not attach any protocols to
that port, IPv4 or IPv6.

How to recreate:
1. Configure a bridge with one network card and set it to No Link and IP Setup
(Bond Ports)
2. Plug the cable into an IPv6 enabled network
3. Type ip -6 a
4. Notice that routeable IPv6 addresses get assigned.

7: br1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group 
ip -6 a
...
7: br1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group
default qlen 1000
    link/ether 10:7b:44:91:3e:c9 brd ff:ff:ff:ff:ff:ff
    inet6 2603:3024:XXXX:XXXX:XXXX:XXXX:XXXX:37b8/64 scope global temporary
dynamic 
       valid_lft 299sec preferred_lft 299sec
    inet6 2603:3024:XXXX:XXXX:XXXX:XXXX:XXXX:3ec9/64 scope global dynamic
mngtmpaddr 
       valid_lft 299sec preferred_lft 299sec
    inet6 fe80::XXXX:XXXX:XXXX:3ec9/64 scope link 
       valid_lft forever preferred_lft forever

/etc/sysconfig/network/ifcfg-br1 contains the following:
IPADDR='0.0.0.0'
MTU='0'
BOOTPROTO='none'
STARTMODE='auto'
ZONE='external'
BRIDGE='yes'
BRIDGE_PORTS='eth1'
BRIDGE_STP='off'
BRIDGE_FORWARDDELAY='15'

I know IPv6 can be disabled via sysctl, but it should also be possible in
YaST2. This can be a security issue, as it is for me.