I'm using Forest 5.05, Vray 3.30.05, and Max 2014.
I send the the job by backburner for my machine only and it did the first frame ok, but the other frames it have the same issue. And the other test i did, if i render the frames directly in my pc the result is ok, so i assume is an issue with backburner or network paths. Do you know how the mesh mask is generated, it's some kind of map that is save or go direct to memory.
Follow the test file i'm using.