Let me state it clearly. The entire button to remove ANY accessory in the HOME kit app is missing. It does not matter what brand, or what accessory it is. There is simply NO button where everyone says there should be such a button. But, I was on with tech support for an hour. Seems they know about this bug and have no idea why it happens or how to fix it short of deleting everything, and possibly wiping the entire phone. It is not that big of a problem to see a device that no longer works, to wipe it all and MAYBE see if that helps.
So, unless anyone actually knows something, consider this topic closed. If your search brings you here, and there is no reply from me saying it was fixed and how, then it is still an issue they can't fix. Merry Christmas.