Ubuntu 16.04 reboots on boot after successfull build

Hi all,

I did some good builds on 16.04 in the past and the builds still go
well but after it reboots it keeps rebooting when it tries to start
from disk and keeps doing this.

Is this something wrong in the latest Preseed templates ? I'm actually
clueless where this could go wrong.

Any tips are welcome.

Thanks!

Matt