[SOLVED] Brightness/reflection difference with same texture and extruded object.

[ChiliBeef]

I've looked online about this and the results I found were not relevant nor helpful in explaining how to fix this issue. So I'll ask here and hope someone can provide some insight on this.

I'm trying to make an inner door panel. I'm using the same texture as the inner walls. If I cut out a section of the inner wall to be the door or even extrude the wall and then separate the selection, the material always becomes incredibly brighter and very reflective. Why? The thickness of the object is the same (online searching found this might be an issue, but not in my case). I'm using the default lighting in the scene, I haven't messed with anything there. Vertex color is set to 0.5. I have not messed with the levels of anything on the material, so why is it doing this?

The only way to circumvent this is to create a new mesh and form it to be the shape I want.

[ external image ]

Is there something dumb in Blender to where you can duplicate an object, slightly adjust it, and it thinks, "Right, it's from the same object and has the same material, I'm going to just brighten it up and make it more reflective than a mirror." ?

[galimim]

Check vertex colour. Should be 0,5.

[ChiliBeef]

Vertex color is at 0.5.

[MatzeH]

Maybe try to recalculate vertex normals.