Comment # 3 on bug 914517 from Marius Tomaschewski

Please ensure, that DHCLIENT_SET_DEFAULT_ROUTE=yes is set either in ifcfg-$name
file or in /etc/sysconfig/network/dhcp.

When it is set to "no", it is a configuration issue [-> yast2-network]; please
provide logs using save_y2logs as described at:
  https://en.opensuse.org/openSUSE:Report_a_YaST_bug