wicked changes the client-id when I`m upgrading  via "zypper dup" from Leap
42.3 to 15.0. After the upgrade, my interface has 2 addresses assigned:

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc pfifo_fast state UP
group default qlen 1000
    link/ether 52:54:00:6b:01:38 brd ff:ff:ff:ff:ff:ff
    inet 192.168.199.209/24 brd 192.168.199.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet 192.168.199.210/24 brd 192.168.199.255 scope global secondary eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::5054:ff:fe6b:138/64 scope link 
       valid_lft forever preferred_lft forever

I tracked the problem down to a change in the client-id in
/var/lib/wicked/lease-eth0-dhcp-ipv4.xml

before update:

<client-id>01:52:54:00:6b:01:38</client-id>

after update:

<client-id>ff:00:6b:01:38:00:01:00:01:23:7c:6b:35:52:54:00:6b:01:38</client-id>

After rebooting the old address (192.168.199.209) is gone from the interface.

I guess this is not a very common use case, but this behavior is breaking our
upgrade tests for the OBS Appliance images.