@blanchg when I try to use proxy with the particle system, I encountered this strange problem. The plane renders correct when it's used just as a plane, but when I use the plane to scatter objects with a ParticleSystem modifier, it renders all black.
Blend file attached for your investigation, I have replaced the external proxy with a simple cube, because I don't know how to embed the proxy in the blend file, but the problem is the same with a cube as with an external proxy. BTW, thank you 3000 for your work on this wonderful addon.