Might be wrong keyboard height

[Wh1rlw1nd]

Hi, I am getting a bit strange (unusuable results) for this:

RxKeyboard.instance.visibleHeight
         .drive(onNext: { [weak postCommentContainerConstraint] keyboardVisibleHeight in
             print("Keyboard visible height \(keyboardVisibleHeight)")
             
             self.view.setNeedsLayout()
             UIView.animate(withDuration: Constants.kCommentBoxAnimationDuration) {
                 
                 postCommentContainerConstraint?.constant = keyboardVisibleHeight
                     self.view.layoutIfNeeded()
                   }
         })

postCommentContainerConstraint is constraint that defines distance between custom view bottom and a container view bottom. If I hardcode value, it works as it should. A pic from storyboard:

the output is:

Keyboard visible height 291.0
Keyboard visible height 335.0
Keyboard visible height 0.0
Keyboard visible height 335.0
Keyboard visible height 0.0
Keyboard visible height 335.0
Keyboard visible height 0.0
Keyboard visible height 335.0

The thing is the actual visible height of a keyboard (along with a toolbar) is around 260.

Why I am getting different and wrong values?

My current setup is, I have a tabbar, and a tableview. Over the tableview I have a custom view with a textView.
I want to slide it up and down as keyboard shows/hides.

What am I doing wrong?