Mix material with alpha problems

[Bulwerk]

I think I have come across a bug.

It appears that when using a mix material with an opacity matte (in my case pine needles on a tree) the Z-Depth does not read through that material.

Is there a setting I am missing? or does this have to do with the background?
Notice that some trees needles appear correct, i checked and those are the ones with a single material.

See images for example

Z-Depth with mix materials

RGBA with mix materials

[aoktar]

i have checked and you're right. Octane loses alpha channel effect on mixmaterial for z-depth buffer.
I'll report this

[Bulwerk]

Thanks aoktar!

This fix would have some compositing work i am doing allot more accurate and easy.