UEFI Boot order options missing from Hyper-V host

I have two 2012R2 Hyper-V Hosts. On one of the hosts, I have no options to set UEFI Boot order, either on existing virtual machines, or on new ones. On the other host, all options are available. I have a series of powershell commands I run to create a Gen 2 VM.  Here is the output from the good Hyper-V host:

Here's the output from the bad host:

I am unable to add any boot entries, or modify:

Set-VMFirmware : The operation is not available.

So, something is wrong with this particular Hyper-V host, but I don't know what to troubleshoot - any ideas?