Now that we had properly set up the ACL for the SPListDataProcessor script, you would think we would be out of the woods. But we were not. Although the Topic table is accessible by other components already in use on the public portal, getting a list of records from this table was not working in the drop-down.
So back to the browser's developer tools to locate the issue. We were getting an error on access to the Topic table.
We added a new ACL to the Topic table to allow read access to Topic for users with the public role and then queued it back up for retest.
Sure enough, another error. As part of the security release from May 2025, the platform was updated to include query_range ACLs to restrict access to tables from Reference fields.
Here are a few links that talk about the update and working with these types of ACLs:
We worked with ServiceNow through a support ticket and found that the *.* deny-unless ACL was restricting the access to this table. The workaround was to include two ACLs specific to topic.name that covered both Deny Unless and Allow If scenarios. Adding these rules with the public role and a script set to just return "true" did the trick.
Finally! Our result was the drop-down variable would allow public users to select a Topic on the form.
