Siri Shortcuts not appearing in Home app automations

I have an alarm.com based security system. I've already created 2 Siri Shortcuts, one to arm the system and another to disarm it. They work fine on their own.

My entire house is HomeKit enabled: lights, shades, thermostats, HVAC, etc.

I am trying to create an automation to automatically arm the disarm the system based on whether or not we are home. I cannot find the Shortcut app as an option to choose from when I build the Automation in the Home app. The steps I follow are:

Open Home app

Go to Automation tab

Hit the + sign

Set the trigger to "People Leave", I set the needed parameters, hit next

Scroll down all the way to the bottom and hit "Convert to Shortcut"

Click into the search box, I get a listing of apps available to me e.g. Calculator, Calendar, Contacts, etc. Shortcuts is not listed in the list which seems counter intuitive!

Is this the expected behavior or am I missing something? It seems logical that I should be able to run a shortcut from a Home Automation.

Any pointers would be greatly appreciated.

Thanks