hmmm UV mapping shouldnt have affected it..interesting. Try Edit>delete by>shader. This will clear the shader then try to apply it again. I have had trouble lately with Maya assigning shaders I had used but deleted..when I applied new ones it came up with the old shader...even though it didnt physically exist. Delete history etc as well. Sometime they just flip thier lids and corrupt..I have had this many times though usually in big scenes. Let us know how you went mate
cheers bullet
bullet1968
"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes