Terrain has several "terrain like" invisible meshes

Hello,

I was looking at my scene, and i decided to view the wireframe and discovered something weird with it...
Seems like there are several "Terrain like" meshes on top of the terrain ( I'm not talking about the LOD terrain mesh ). These also update if the camera is moved.



The wireframe on top of this building isn't from the building itself. It's from the "terrain like" meshes.



This weird wireframe is also displayed on top of other geometry, which should never happen.

If i create a brand new terrain, this also happens.
It doesn't happen in a different project though.

I'm also afraid this might be slowing down performance...

Is there a way to fix this? Has this happened to anyone?
( I could try to send a bug report, but i would have to delete so many things, so i want to see if anyone know what's happening here )

Thanks for the help.

 

Bump.

 

what material/shader you have on those buildings? (at least with some transparent shaders, the wireframe shows through..)

 

The majority of objects use Lux bumped specular shader.
Only the "terrain like" meshes wireframe goes through all other objects. Everything else is as it should.
For the terrain, i use RTP, but i already talked with the creator and he said RTP is not the cause of this.

If i disable the terrain, the "terrain like" mesh also disappears.

 

Bump again...

Since this weird mesh is visible through all other objects, i put a simple cube in front of the camera to be able to see it better..
This mesh is really really weird...

Does anyone have any idea of what this thing is?