annotationView.center sometimes gets a new point, sometimes gets an old point

I'm trying to get a new value on annotationView.center. And it sometimes returns the last location that I have already got. It was working fine before iOS 15.3. But after iOS 15.3 update, it started to be intermittent.

Code:

     [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
         if let annotationView = object as? MKAnnotationView { 
             let position = annotationView.center
         }
}