I would get this strange error which i couldn’t Google out every time i would try to install Windows on additional IP:

The unattend file Z:\unattend\169.254.69.148.xml was not found!

You would probably get a different xml name, corresponding to some other IP, and the installation would abort.
The solution is simple. You probably have 2 network cards defined (i had legacy and a standard network card), so the system is trying to install via regular card instead of the legacy one. Remove the standard card and leave only the legacy one for the installation.
And that’s it!