navisworks autodeskrendering middle , high, error???software bug???

[905053963]

hi, i have some question for navisworks  autodeskrendering.

the first image is autodeskrendering high quality.

the second image is autodeskrendering middle quality.

The first high-quality but does not look better ， through the glass not see the room's GI.

These two pictures are not a big  difference, except autodeskrendering quality.

Other examples：

low quality

middle quality

 high quality(with a glass have some other reason?)

I want to know why this happens. Is set error or software not perfect reason?

Thanks for your help in advance.