What is this leaf showing?

You have 2 mars hydro at 17 inches.......i'd say too close upper leaves bleaching and becoming "3d" looking are signs of light stress. Notice how the plant in the back isn't affected, because its not directly under the light. In veg I usually have to keep my light at 23 inches to avoid light stress. In flower i'll go down to mabye 18 depending on how they take it. Happy growing.