Fios Digital Voice Calling Features Parental Control doesn’t work on all of my STBs

I have an annoying brother who keeps turning on calling features on our phone line. I setup parental control PINs and every one of my STBs asks for the pin in the calling feature section of the widget except his STB which is an IPC1100 P2. It lets him right into calling features and he can change them. What would cause just one STB to not enforce parental controls on this widget?