20.7.7_1: VM not responding to ACPI calls

[MBfromOK]

OPNSense Version:OPNsense 20.7.7_1-amd64 (and previous)
[freeBSD Version:[/b] FreeBSD 12.1-RELEASE-p11-HBSD
Hypervisor: Proxmox (6.3-3) - and previous

I have been having issues for a while with OPNSense not responding to reboot / shutdown requests from the hypervisor via ACPI calls, I have been working around it by logging into OPNSense via the WebGUI, but yesterday (after I upgraded to 20.7.7) the web GUI stopped responding, the vm shell console, and internet access went down repeatedly forcing me to down the entire server to force OPNSense to reload.

While trouble shooting I followed a guide from Proxmox for Linux VM's that basically said to make sure acpi was installed & running.  Since ACPI is included in FreeBSD core I thought it would be quickly resolved.  I followed this page: https://www.freebsd.org/doc/handbook/acpi-overview.html to verify that terminal acpiconf calls responded in a useful way (they did), however, OPNSense is not reacting to calls from the Hypervisor.

Other VM's (Debian) on the same server respond without issue, how can I troubleshoot the communications for this VM? 

[Voodoo]

The problem probably is that you enabled "Qemu Guest Agent" in the proxmox vm options.

Proxmox doesn't send acpi commands if it is enabled, it will wait for the agent to respond until it timeouts.