iOS 8 view controller presented via UIModalPresentationCustom cannot itself present any view controllers? Also unable to dismiss

Question

In iOS 7 everything worked as expected. With no code changes, in iOS 8, my menu view controller cannot itself present any other view controllers and prints an error to the log when I try and dismiss it. When I try to present more view controllers on the stack, from within the VC that was presented using my custom transition, I try to and simply nothing happens, as if I'm calling methods on nil when I'm not. Here's how I present it:

// Get menu from storyboard
UINavigationController *modalViewController = [self.storyboard instantiateViewControllerWithIdentifier:@"MenuNavigationController"];

// Set self as transition delegate
modalViewController.modalTransitionStyle = UIModalPresentationCustom;
modalViewController.transitioningDelegate = self;

// Present menu
[self presentViewController:modalViewController animated:YES completion:^{}];

Then, when I try to present more view controllers from within the presented menu vc, nothing happens in iOS 8! However, when I try and dismiss my menu that has been presented in a custom fashion I get this in the console/log:

attempt to dismiss modal view controller whose view does not currently appear. self = <UINavigationController: 0x7f90e8f5b210> modalViewController = <UINavigationController: 0x7f90e9bf63b0>

Any ideas? What's different between iOS 7 and 8 when it comes to presenting a view controller modally using a custom transition? The main problem I'm trying to solve is that I want my menu to be able to push on additional view controllers just like it has always been able to do in iOS 7. I also need to figure out how to dismiss the menu VC without error!

Any ideas?