This is the actual cause for the issue. The delay is a workaround. this is documented I just did not understand it: "Calls to the API only prompt when the application state is UIApplicationStateActive." (https://developer.apple.com/documentation/apptrackingtransparency/attrackingmanager/3547037-requesttrackingauthorization)

The delay is a workaround. The actual issue is that the request has to be called when the application state is UIApplicationStateActive. This is documented but the significance can be hard to understand: "Calls to the API only prompt when the application state is UIApplicationStateActive." (https://developer.apple.com/documentation/apptrackingtransparency/attrackingmanager/3547037-requesttrackingauthorization) so make the call in "applicationDidBecomeActive"and all will be good.