Scenes that contain custom shaders for volume effects or environment shader may not render correctly with advanced filtering (quadratic, quartic, etc.) for file textures.
Use mipmap filtering, or turn off filtering.
Imported or referenced Maya 5.0 files containing mental ray shaders, with color, scalar, or texture parameters, do not correctly convert in the current release of Maya. You may notice shaders becoming disconnected.
Open the Maya 5.0 scene file in Maya Interactive, and save it. Then import or reference the file in the current release of Maya.