Hi! i don’t know if there is a bug in there but from what i can see you don’t need the “color2 bump” map there becasue your map is already with black and white values. You usually use that map when you wnat to “extract” bump information out of a color map since you don’t have a proper bump map.
So in the meantime it may be a solution to not to use the “color2bump” map.
We did some more testing and managed to reproduce the same behavior on our side.
Adding the following environment variable to your system should produce the same result as the one you got with V-Ray 3.30.03: