Light cache, backburner problem

Hi, I posted this on the public forum earlier with no success as I hadn’t been verified.

I’ve been doing some renders with light cache as the secondary bounces, and have lined up 4 cameras as batch rendering on my local machine. However the renders come out a lot darker than my individual test renders.

I can’t work out what the problem is since the paths should all be the same as when I do individual renders within max. Not sure whether it’s the gamma or the light cache that is not working properly.

I’ve done some experimenting and have found out that if I send the render jobs to backburner one at a time then it renders as expected so it seems that the problem lies with 3ds max native batch render.

Can anyone help me out here?