MacBook not staying associated with profile

I love the Xfinity Internet Profile feature, especially how I can turn the wifi off at a certain time. Unfortunately, every couple of days my MacBook Air keeps showing up as a new device, so I have to manually add it to my profile. This happens all the time and even if I add it to my profile with the wifi time limit, it may appear as a new device that night when the wifi is supposed to be off for the device. I cannot set a wifi schedule for the whole network since I am not the only person in my household. I called Apple Support and there was nothing in my settings that stood out. I've been trying to call Xfinity Support but lord knows that's impossible. I'd love to figure this out!