Motion zones cut off on 21:9 phone

I have an Xperia 5 II phone. The screen has a 21:9 aspect ratio. When adjusting motion zones in the app, the camera image does not properly fit in the screen. As a result, I can only create motion zone for the lower part of the camera's view. See the attached image. It shows how motion zone editing is cut off and how the resulting zone covers only the lower part of the view.