OK, someone please reproduce these steps to see if I have found a bug in the use of lights.
1. Place 4 objects/pix in 4 groups. Arrange them in depth on the Z axis.
2. Create a light-spotlight that is red and adjust its fallout to fall only on the first object.
3. Create another light-spotlight and make it blue and move it on the Z axis to affect only the second object.
4. Do this with 2 more lights for the last 2 objects using two different colors for each.
The bug is...the first light illuminates Object 1 with red as it should.
When light 2 is activated all objects become fully lit white. If you change it to point light then things appear as they should...Object 2 is lit blue. But try and add Light 3 as ANY kind of light and all objects become fully lit white. I have searched all parmeters and played with many variables...I am left with the perception that the lighting in Motion 3 is severely flawd.