Before you render with GI, turn off all your lights and do a quick test render. This way you can see what objects have materials which use ambient or alternate diffuse/specular. (I guess you can go through all the materials, but this is probably quicker.) I'm pretty annoyed with how many flesh textures use these tricks. It really messes up GI. One could write a script to autmatically remove them, but there are cases where they are desirable.

Yep, that bothers me a lot too.  Annoying to have the character glowing like lava in a dim light setting.

There are quite a few hair models that use either ambient or translucence in their shaders. This also slows down IDL calculations. I have to go in and rework the shaders and save the material collection.

Quote - There are quite a few hair models that use either ambient or translucence in their shaders. This also slows down IDL calculations. I have to go in and rework the shaders and save the material collection.

Does translucence also mess things up?

Quote - There are quite a few hair models that use either ambient or translucence in their shaders. This also slows down IDL calculations. I have to go in and rework the shaders and save the material collection.

I've had that happen too... what changes do you end up making, if I may ask?

Well, I'd go in and turn off the ambient and/or translucence channel and unplug the connections to the texture map. I'd leave the texture map plugged into the Diffuse channel. Then I'd add an blin node to the alternate specular and attach the texture map to the bump channel. Now I've been using the shader set up from Bb's VSS Hair prop.