Post Processing conflict

I have two materials.

Material A is surface transulecent material. It has “Allow Custom depth writes” Checked on.

Material B is post process material using the node “SceneTexture Custom Depth”.

Material B shows up on Material A until I disable the material in the Post processing volume.

I guess I don’t understand how this works. Is there way to get Material A to show up?

I was trying to using Material A as a window to see, objects.