I'm unsure if this is an issue with HASS.Agent or just home assistant but here goes. I have a button I had made "Shutdown PC" which calls the following in scripts.yaml. This previously worked but must have stopped working recently. I presume an update with either Home Assistant or HASS.Agent broke it, but I don't recall seeing anything in breaking changes relating to this.
I think it's due to changes in HA, not HASS.Agent. It wasn't worth troubleshooting so i ended up deleting that config and instead sending basic CMD commands (eg shutdown /s /t 20, shutdown /r /t 20) via HASS.Agent.