Strange behaviour in 0 bounces Direct lightning and two lamps.

Hi, while trying to setup the render settings to have a fast texture preview in cycles (somehow, the textured and material options in 3dview doesnt work in my laptop), I’ve encountered a strange behaviour. I dont know if it is a bug, though.

I’ve set the sampling options to 0 bounces to mimic the BI rendering, black enviroment, and one point lamp (size 0). Everything works as expected, I have a noise-free image with just one sample (aliasing beside). But if i add another point lamp, to fill the black areas, a very ODD (pun ahead :slight_smile: ) thing happen. The image is noise-free in even number of samples, but noisy in ODD numbers. Maybe its not a bug, but a lack of optimization, but i thought it would be worth knowing why.

The first image is with 3 samples, and the second one is with just 2 samples:

http://imageshack.us/a/img213/5323/dl3s.th.png
http://imageshack.us/a/img203/1880/dl2s.th.png

Blend file: http://www.pasteall.org/blend/17956

Any ideas why does this happen?