iOS7 UIModalTransitionStyleFlipHorizontal bounces after transition

This appears to be a UIKit bug. The following workaround seems to resolve the issue for me.

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];

    [self.navigationController.navigationBar.layer removeAllAnimations];
}

(Place this in the view controller you are transitioning to).