It seems the "Work Item Created" trigger doesn't work for tickets that are created from an automation rule in Assets (only works if ticket is created within Jira or from email handler).
For example, we have an automation rule in Assets that creates a ticket in a service project when a contract (object) in Assets is 90 days from expiration. I have an automation rule set up to automatically assign the request type based on text in the summary. The automation rule only works if I create the ticket manually in Jira, or a ticket is created from email; it does NOT work if a ticket is created based on the automation rule in Assets.