Annotation is selected works 1 to 2 times when map region change to Center pin and not work all times

I have problem in Annotation View When i tap First time in Annotation it callout perfect and set Annotation in Center of MapView but after i change Region and Again i click on Annotation it just center on mapview but now callout bubble. Please check below DidselectAnnotationView method is there any problem.

-(void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)view
 {

    region.center.latitude =  view.annotation.coordinate.latitude ;
    region.center.longitude = view.annotation.coordinate.longitude;

   CLLocationCoordinate2D pointLocation =
  CLLocationCoordinate2DMake(view.annotation.coordinate.latitude,     
  view.annotation.coordinate.longitude);
  [self.mapViewAlert setCenterCoordinate:pointLocation animated:TRUE];

   [(MKMapView*)self.mapViewAlert selectAnnotation:myAnnotation animated:YES];

  }