I did not see the echo plus with it's hub features until the day my first order for P Hue starter kit with hub shipped. I ordered the E Plus with the included P Hue bulb, and waited until it was all in before installing. After setting up the E Plus (not my first echo device), I did discovery on the bulb shipped with the E Plus and it worked like a charm. Then I plugged in the 4 bulbs from the starter kit. Many attempts later, not one of them was discovered. Best I can tell, they are all exactly the same model bulb. On a lark, I decided to set up the Phillips Hue Hub and install the app. It discovered all four bulbs (telling me that they were all discoverable). After setting up the P Hub on the Echo Plus, the Alexa app put all 5 bulbs in one group, as I wanted, and I can control all five as if they were one hub. There is strong evidence that there is a difference in the bulbs in how they interact with the hubs.