Hello! When I add a skybox at my scene there are some models that have a strange reflection , like they lose their color. When I am changing the cull mode to back faces it reflects a little better but that is not a solution. I am using a single material at the scene and I dont have any specular maps. Also I have set glossiness to zero. When I remove the skybox reflection and color is fine. Which setting am I missing?
It may be a problem with your model and its normals. If you play with Culling on your model and toggle between Front/Back you will see the polygons being flipped quite often.
When you don’t use a skybox for lighting that doesn’t show so much but it’s still there.
Try fixing your nornals to always points outwards and see if that fixes it. Here I applied a normal radial modifier in Blender just to see if your issue is normals related: