Strange UINavigationController push behavior due to custom UIFont
===

I have changed the font of the UINavigationBar using 'appearance' available in iOS5. But when doing a push transition to another view controller (using Storyboard) it goes wrong. During the transition, normally you can see 'fade in' the next UIViewController's title, but now all I see is 'F...' and only at the end of the transition the whole title show up: 'Facebook sharing' (instead of immediately).

Anyone who has had this problem before? This doesn't happen when there's a UIBarButton on the right of the UINavigationBar. Then everything goes fine.

I set the font like this:

    UIFont *fontName = [UIFont fontWithName:@"Chalkduster" size:0];
    NSDictionary *font = [NSDictionary dictionaryWithObjectsAndKeys:fontName, UITextAttributeFont, nil];
    [[UINavigationBar appearance] setTitleTextAttributes:font];