Bug: Materials with $decal render in front of portals when applied to brushes as appose to behind.

[L9M2]

Describe the bug

I was making a map with a decal to mark where portals were. The decal was a simple texture that was transparent, and if you give it the $decal material property it's suppose to render slightly offset from a brush so it prevents z-fighting, similar to the info_decal entity. In this one instance I had to place a decal on a moving brush, info_decal doesn't work with brushes correctly so I had to apply my material to a custom func_brush to overlay on top of the other brush.

To combat the Z-Fighting I gave it the $decal parameter, but to my surprise the decal renders in front of portals! This is unlike when I haven't had the $decal parameter applied as it would render behind the portal, and even the info_decals render behind portals.

Below Image is what a material looks like with the $decal parameter applied. Notice how the decal renders in front of the orange portal. (Removing the $decal parameter fixes this)

Below image of the same material applied to an info_decal entity. Notice how it renders behind portals as intended.

Issue Map

N/A

To Reproduce

1. Create a "LightmappedGeneric" with a decal property.
2. Place it on a func_brush
3. Shoot a portal on it.
4. Renders in front of portals.

Workaround I found :

Don't give the decal property and offset the material's brush by 1 unit (To combat Z-Fighting). Despite it being a unit off, the materials still renders behind portals.

Operating System

No response