Problem Description Location-based notifications added with UNLocationNotificationTrigger and CLCircularRegion do not fire consistently when the user enters the monitored region. Sometimes they work, sometimes they do not. In tests where the user physically enters the region and waits several days, the notification often never triggers. What we’ve confirmed Notification permission is granted Location permission is set to “Always” The notification request is successfully added (no error from UNUserNotificationCenter.add) Pending notification requests are present when checked with getPendingNotificationRequests CLLocationManager didEnterRegion / didExitRegion work when we monitor the same region via startMonitoring(for:) UNLocationNotificationTrigger behavior is inconsistent and unreliable in our tests Reproduction Steps Launch the app and grant notification permission and “Always” location permission Add a region notification (either by current GPS location or by selecting a point from MKLocalSearch) Leave the monitored region Later, physically return into the region Expected: a notification is delivered when entering the region Actual: the notification often does not appear, even after waiting days Our Hypothesis: Coordinate System Mismatch in China We suspect the issue may be related to coordinate systems in mainland China. In China, Apple MapKit and MKLocalSearch use GCJ-02 (the “Mars” coordinate system required by local regulations). Device GPS and CLCircularRegion / Core Location use WGS-84. If an app supplies GCJ-02 coordinates to CLCircularRegion (e.g. from MapKit or search), the region center may be offset by hundreds of meters from the actual WGS-84 position. That could make the system’s “inside region” check fail, even when the user is physically inside the intended area. Questions for Apple Does CLCircularRegion (and therefore UNLocationNotificationTrigger) expect coordinates in WGS-84? If so, should apps in China convert GCJ-02 to WGS-84 before passing coordinates to CLCircularRegion? Is there any official guidance or documentation for handling coordinate systems when using location-based notifications in mainland China? Are there known limitations or special requirements for UNLocationNotificationTrigger in China (e.g. coordinate system, accuracy, or system behavior) that could explain intermittent or missing triggers?