UINavigationController Freezes

So I have this very simple code.

//Push the uiviewcontroller of the juice
JuiceViewController *viewController = [[JuiceViewController alloc] initWithNibName:@"JuiceViewController" bundle:nil];
//Set the object tot os displaying
viewController.mProductRef=juice;
//Push the view controller
[navController pushViewController:viewController animated:YES];

It works 90% of the time, the other 10% the screen freezes, but the app does not crash. The navigation did happen its just the animation that freezes.

I know this because if I do the side swipe to go back the screen pop back in to the correct form.

Like I said 90% of the time it does what I expect but sometimes it freezes.

I have never seen this before in any of my project. Does anyone have any idea what this could be?

Thanks in advanced.

via Chebli Mohamed