I asked the Home app developer this Q. He said that its in the way the Hue bridge characterizes it. I believe he said that technically the bulb has a "service" which is the name you stated in the Hue app. But the device name is different -- that's what shows in the Home app's list. You can rename the device itself but the name has to be different from the "service." So you'd have to come up with a different name. Weird.