Maya :: Color Management With OpenEXR - Masterlayer Passes Washed Out

I have recently discovered what I think could possibly be a bug when using the OpenEXR format with Mental Ray passes and color management in Maya 2011 & 2012.

For example If I create a scene using the below steps:

1. Enable Color Management (default linear work-flow)

1. Create a sphere and assign a Maya material or a mia_material_x_passes shader to it (textured)

2. Add the sphere and light to the masterLayer or any custom layer.

4. Create a beauty pass, and associate with layer

3. Change the output image format to OpenEXR

4. Render and the color looks correct once a gamma correction of 2.2 is applied. See image attached goodColorSpace.jpg

However, If I add a (CGpost) pass to the same layer; for example a cameraDepth or Object Normal. The color space for the beauty and even the masterlayer passes are all washed out. See image attached badColorSpace.jpg

It seems that when using Color Management and combining (illumination) and (CGpost) Pass Groups in a single layer with OpenEXR is creating this outcome.

I should add that changing the frame buffer dose not work either, same result with 8bit Int --> 32bit Float.

I have attached 2 images which show that by simply combining a CPost (cameraDepth) pass with an Illumination (beauty) pass creates a very different looking color space.