This has probably been reported already but in case it here are a couple of screenshots of when randomly one item of something will be lighter in colour as if in sun while nothing else around it is illuminated in the same way.
as you can see in the second image i have the ground near it selected so it isnt even selecting it that makes it go the lighter colour.
sorry if in teh wrong place mods do with this post as u see fit n if u wanna just move the pics to another thread be my guest 
edit: on alpha 4