[NEEDS INFO] skybox vs no skybox

I have encountered a problem. when I make a map, if I include a skybox, the shading is different than when there is no skybox. with the skybox, there are little to no shadows, and light sources seem to stay one brightness no matter what I set them to (I tried setting one lamp to a brightness of 50, and another to 5000, as as far as I could tell, once the map compiled, they were the same brightness.). when there are is no skybox, there are strong shadows, and lights are a lot closer to what their brightness should be.

also, when I set noshadersun and define a sun lamp, it fixes these problems.

I will post some example pictures of what I mean later.

I suppose your problem depend from the light coming to the skybox ... i don't think there are other explanations for this kind of problem.
I try to explain my pov because i've got a similar problem some time ago testing some skybox made by me.
When you have a high amount of light coming from the skybox the shadow will be few becasue usually there a lot points of light.
The opposite when you put only few point of light and NO skybox ( and example is a black skybox ) ... in this case the few point of light make shadow more marked and the illumination condition will be very different and in some cases very unreal.

You sad the shading is different when you use a skybox ... yeah, is normal because all the light coming from the skybox make a "real" lighting condition instead putting only a light in all your map.

Btw if you post an example ( a screenshot ) is perfect to understand your problem.
I hope to be clear