After setting a static ip address in a debian based os, there is often a secondary ip address visible with
ip addr show.
This is caused by the
dhcpcd service which keeps running after setting a static ip.
Stopping this service will remove the secondary ip address after a reboot or network restart.
update-rc.d dhcpcd disable service dhcpcd stop #and optionally the next line or a reboot ip addr del %YOURS-SECOND-IP% dev ethX
%YOURS-SECOND-IP% with the unwanted secondary ip address.
ethx with the interface name.
Restart the network.
Or just reboot and the secondary ip will be gone.
Works on a Volumio based Raspberry Pi and Ubuntu Server 18.04.2 LTS.