We've recently completed a migration from Jira Server to Cloud. We have established separate object types for Departments and Applications, created Insight custom fields intended to house each, and have made those fields visible on the screens where we need them. The problem seems to be assigning values to those fields within automation.
At the moment, my understanding is that if I enter an IQL query in the field assignment box, whichever object is returned by that query should be assigned to the field.

I'm not sure if my syntax is incorrect or what, but regardless of what I type in the field assignment box, Jira throws an error "An unknown error has occurred. Please reload and try again." Reloading has no discernable effect.

I can manually select objects when interacting with those Insight custom fields on an issue edit/view screen, so I know the filter scope is correct.
Any advice on how to address this?