Hi Ravenous,

Animation is definitely a learned process. The cardinal rule is to double check that you are always on frame one prior to making changes on any object that is not supposed to change over time. If you accidently do make a change to a shader (or anything else) while the playhead is in the middle of the animation, you can simply delete the offending keyframe. You can even drag a marquee selector across multiple keyframes to select more than one. 

Carrara automatically keyframes. So, if you changed the color of the car mid animation and then continued to animate the motion of the car, the shader itself won't be automatically keyframed even though the motion of the car is. 

Mark