3D Touch, Peek & Pop with different frame sizes

Question

I implement peek and pop to view photos.

I set the option to view the view in PDF to fit the photo in

- (UIViewController*)previewingContext:viewControllerForLocation:

Everything looks fine:

And just click it as viewControllerToCommit in

- (void)previewingContext: commitViewController:

But when I commit pop, I get a view controller with the wrong size:

Typically, a view controller should look like this:

I tried setting the frame size and preferredSize to

- (void)previewingContext: commitViewController:

but still not working.

To avoid this, I should not install preferredContentSize or create a new view controller without installing preferredContentSize, and this is not ideal.

Am I doing something wrong here?