Hi @WT_9387121 ,
When I am looking on the provided picture, for me is not clear what is the direct implementation.
Is this a 3D Panel with buttons widgets on it? What kine of button widgets or is this some 3d images where the click event is used (so used as button) So, I think further information about the used widget could be here helpful to understand better the problem.
One trivial reason could be that they are placed on the same plane in different order and sometime depending on the render mechanism on a specific platform some widget are clipped. In this case you can smile move the button to the front direction