This has been like this since solstice came out with it's armor but unlike previous years where each piece has 3 versions (white glow, color glow, no glow.) You seemingly only have the color glow if you bought it and either the white glow or no glow depending on how much you upgraded pieces during solstice. For my titan for example I got the head and shoulders glowing but not the rest so I want to transmog all non glowing pieces to match the set better but I can't because I can't transmog non glowing versions when I obtained the glowing on.