When building hosts, the templates get rendered using a token that is valid for a certain amount of time.
This token is also verified in the "built" template, which is suposed to flip the host from "in build" to "build finished".
Thus if you start your deployment while the token was still OK, and it expires during the build, the state will not be switched and the machine will boot in build mode again on next reboot.
The new build will error out, but the machine will remain in the booted broken build system and will not boot from local disc.

The problem is because of:
The unattended "built" template calls "find_host_by_token" which calls "Host.for_token(token).first" (see app/controllers/unattended_controller.rb)
for_token is defined as
scope :for_token, ->(token) { joins(:token).where(:tokens => { :value => token }).where("expires >= ?", Time.now.utc.to_s(:db)).select('hosts.*') }
(in app/models/concerns/hostext/token.rb upstream, app/models/host/managed.rb in satellite 6.2)
thus the host is never found and the "built" mode flip is never executed.