I've been consistently having a problem with HomeKit devices, scenes, and automations magically vanishing overnight. When I add the devices they are fully functional at first but eventually they just disappear (usually when I'm sleeping). It also is gone from the manufacturers app. I can add the device back in as many times as I want but it continues to do this. Sometimes it stays but I cannot figure out any rhyme or reason to this problem. Any ideas?
Homkit devices disappearing overnight
User-centric queries/comments such as this are perhaps best put to Apple's public community support forums, where Apple/AppleCare tends to monitor user comments, and/or Apple's twitter support account, vs. risking off-topic here in the dev forums, thanks and good luck. Users can feedback via http://www.apple.com/feedback/ - Devs using betas are free to use the 'Report Bugs' link, below right.