REST Endpoint Scanning Displays Deceptive Message

If you add a REST Endpoint to a package in your script roots marked for REST Endpoint scanning, as described in the documentation and click "Scan" on the REST Endpoints page, the REST Endpoint will be added as normal. However, you'll receive a pop-up message saying "No REST Endpoints were added or removed", which is deceptive. The same thing happens if you remove the endpoint's file.