i've used the uwl04 with nauticam and sometimes i see the hood and sometimes not... i don't know why...... but i sell this lens for poor quality in the corners... :-(
The hood is visible because of the image stabiliser, when you pan the camera the hood may be captured. For what concerns the corners this is a problem of the camera itself to start with. The Zeiss lens has a lot of distortion in the corners, when the distortion is suppressed the image gets soft, this happens in the corners a lot.
The lens then can make this issue worse
It does look like the Inon lens shots are sharper though but that lens is expensive