I would think it should be in the boot log, but I am unsure on that one.

Sounds like that shutdown the system, so the problem is just getting it to power off. You could try "halt -p”. That explicitly calls for the system to power off. If that doesn’t work, perhaps try “halt -verbose”, which will give a bunch of info on the next boot about what halt was doing, might show an error there that could you lead you in the right direction.

Did you use any arguments with shutdown? Does shutdown spin down the system, but not turn off the hardware, or does it not do anything? You can try " shutdown now -h". That should halt the system after a graceful shutdown.