Wireframe conflicts with highlight

See this PG.
https://playground.babylonjs.com/#1KUJ0A#726

For some reason, the wireframe rendering does not work in the highlight render target texture.

One way to make it work is to force to use the mesh material to render in the layer:

https://playground.babylonjs.com/#1KUJ0A#728

See line 31.

In this setup, the highlight color is the emissive color of the material.