Does anyone know what would cause this discoloration? Would it be covered under the lifetime warranty?
Your fixtures are incredibly beautiful. It's a totally normal patina called verdigris that forms on brass and copper as the metal oxidizes over time. If you want to keep it, it may take some time but the extensions will eventually catch up. However, if it bothers you, a brass and copper cleaning solution can somewhat restore the brass to its original appearance. If you go that route, I highly recommend you contact customer service first. They can probably suggest a cleaning product that's safe to use and let you know of cleaning products or techniques that could potentially void your warranty.
