Lightning Question in Space Shooter tutorial

Hey guys

Having a strange issue its not game breaking but it bothers me. When I move the ship up on the z.axis what happens is that the farther that you go to the top of the screen the directional light brightens the ship considerably. When I move further from the top(move towards the bottom of screen) the ship darkens considerably. This never happened before not sure if I accidentally messed with a setting or is this is a new feature. Do you guys know solutions? My light shouldn't brighten the ship nor darken no matter where I move.

Thanks in advance Shindy