IOS Dark Keyboard has background during push / pop animation of UINavigationController

During the push / pop navigation animation of the navbar, the keyboard is darker, then it is in its final state. And at the end of the animation, that black background just disappears. Light (white) keyboard style does not have this effect.

How can I get rid of this black background?

I've already tried setting the window color to white and setting the background of the navigation controller to white.

VIDEO:

https://www.dropbox.com/s/z1grj821fj306th/Untitled.mov?dl=0

SCREENSHOT: