
The Cause: The phone loses its GPS satellite lock for a split second and switches to a nearby WiFi router or Cell Tower.
The Result: The OS (iOS/Android) suddenly reports a location 200 meters away with an accuracy of 100m. Because this new point is technically outside your 250m geofence radius, the SDK fires an EXIT event.
The Jitter: 30 seconds later, the GPS lock returns, and the device "jumps" back to the yad or job site.