We struggle with our DHCP validation code in both Discovery and Staypuft. We are looking into the issues but as a quick workaround, we could implement a simple global setting that would disable DHCP validator which is causing the "DHCP Conflict" screen with Override red button. We will keep this turned off for Foreman Core, but people might turn it on for Discovery or Staypuft deployments until proper soulution is found.