First. I call the "requestGeometryUpdateWithPreferences with UIInterfaceOrientationMaskPortrait" at Portrait , its not going to work. // the phone is Portrait pIOS.interfaceOrientations = UIInterfaceOrientationMaskPortrait; [scene requestGeometryUpdateWithPreferences:pIOS errorHandler:^(NSError * _Nonnull error) {}]; // "viewWillTransitionToSize:withTransitionCoordinator:" will not call Then Next. I call the "requestGeometryUpdateWithPreferences with UIInterfaceOrientationMaskLandscapeRight" at Portrait. Now it will call "viewWillTransitionToSize:withTransitionCoordinator:" twice. // the phone is Portrait pIOS.interfaceOrientations = UIInterfaceOrientationMaskLandscapeRight; [scene requestGeometryUpdateWithPreferences:pIOS errorHandler:^(NSError * _Nonnull error) {}]; // "viewWillTransitionToSize:withTransitionCoordinator:" will call twice The Phone manifested as goto LanscapeRight and immediately back to Portrait Is this a BUG?