iOS 11 - UINavigationItem titleView when using Large Titles mode

Question

I'm trying to understand either it's a bug or it's the expected behavior.

On iOS 10 and earlier we could set up a custom title, using navigationItem.titleView.
On iOS 11, when setting our navigationItem.largeTitleDisplayMode = .always and setting navigationItem.titleView = <Some cool UIButton> it's displaying both the normal navigation title bar and the large navigation title.

Illustration:

To sum up:

How can we use custom titleView on our Large Navigation Title?

EDIT : This is the expected result:

Answer 1

I was able to replace the navigation bar big title with a custom view by using a subclass of UINavigationBar and manually changing the view hierarchy :

@interface MYNavigationBar : UINavigationBar

@end

@implementation MYNavigationBar

// ...

- (void)layoutIfNeeded
{
    [self setupTitle];
    [super layoutIfNeeded];
}

- (void)setupTitle
{
    // UINavigationBar
    // -> ...
    // -> _UINavigationBarLargeTitleView
    //   -> UILabel << Big Title Label
    //   -> UIView
    //     -> UILabel << Big Title Label animating from back button during transitions

    for (UIView *view in self.subviews) {
        NSString *className = NSStringFromClass(view.classForCoder);
        if ([className containsString:@"LargeTitleView"]) {
            for (UIView *view2 in view.subviews) {
                if ([view2 isKindOfClass:[UILabel class]]) {
                    [self convertLabel:(UILabel *)view2];
                }
                for (UIView *view3 in view2.subviews) {
                    if ([view3 isKindOfClass:[UILabel class]]) {
                        [self convertLabel:(UILabel *)view3];
                    }
                }
            }
        }
    }
}

- (void)convertLabel:(UILabel*)label
{
    // I kept the original label in the hierarchy (with the background color as text color)
    // and added my custom view as a subview. 
    // This allow the transformations applied to the original label to be also applied to mine.
}

Please note that Apple might reject your app because of this trick.