Trouble with overridden part colors not showing in assembly

[cmm3]

I have two parts that I assigned a material and changed the color appearance to match the paint, however when placed into an assembly, the colors becomes shades of grey/metallic look. This is the first time I have run into this problem and when trying to create another assembly, the parts still remain grey. How can this be fixed? I am running Inventor 2018

[JDMather]

Can you Attach a file here that exhibits this behavior?

[cmm3]

Here is a simple assembly I just made, All I did was create the shape, set the material, and used Appearance Override on a few faces

[JDMather · Accepted solution]

First think I noticed is that iProperties indicates that you  have not installed the latest updates for 2018.

What happens if you change the Lighting Style to Gray Room rather than Two Lights?