Maya batch rendering with Mental Ray when you have keyframed shader attributes that have set driven keys on them will cause problems . For example I have a blendcolor setup that blends between weights on a MIB_color_mix using a set driven key on a rig.
The fix: The fix is to disable the “Optimize animation detection” option in the Mental Ray render globals “Options” tab under ‘Performance‘ roll out.
This will have a hit on the render times, but may solve issues with keyframed shader / texture attributes.
From testing its about a 15-20 percent increase time per frame during rendering.
