Why is there a brown stain on my new terrain?

Hi, I recently created a new terrain but for some reason there is a brown stain on it, does anyone know how to get rid of it?

Oh in the world outliner there was an object with the same name as my character but with the text “spare” next to it; for some reason this did not have a mesh but it still had a shadow (I did not create this “spare” character). After removing it and rebuilding, the stain is gone.