Thank you for reporting a bug to Unity.
Our investigation indicates the issue originates from a third-party asset, plugin, or service, rather than Unity itself. Because the problem lies outside our codebase, we're unable to address it directly.
We will close this case as a third-party issue. A common fix for this issue is to use Apple's own image tracking samples project https://developer.apple.com/documentation/ARKit/detecting-images-in-an-ar-experience which should correctly set up your environment and ACTool and resolve the issue allowing you to build your Unity apps for iOS.