Você testou isso sem -Kill
? Do Stop-VM
referência do cmdlet :
Indicates that you want to stop the specified virtual machines by terminating their processes running on the ESX. You can use this parameter to stop a virtual machine that is not responding and cannot be stopped or restarted in other ways. To use the Kill parameter, you need to have a direct connection to ESX 4.1 or later.
Encerrar o processo diretamente no host certamente soa como um evento que deve acionar o HA. Acho que eu adotaria uma abordagem escalonada para isso:
# Some condition happens, ask nicely.
Shutdown-VMGuest -VM xxxx -Confirm:$false
...
# Ask less nicely.
Stop-VM -VM xxxx -Confirm:$false
...
# A last ditch effort.
Get-VM xxxx | Set-Vm -HARestartPriority Disabled -Confirm:$false
Stop-VM -VM xxxx -Kill -Confirm:$false