I believe she not only usually makes everything she has invisible but has made other people and objects invisible. She can project it out like her forcefields. I supposed she might have forgotten it was there and not having put thought to it it might have stayed visible but its a stretch. In addition though the uniforms are made from reeds unstable molecules which react to superpowers and is why his clothes stretch and johnys clothes don’t burn away and since its branded I would assume it would be made the same.