BLUF: Make sure “Share My Location (from this device)” and location services for the Home app are turned on for all of your Home app users.
Ok so I think I discovered the issue and it seems to be working now after correcting it.
I was using mainly the “people” parameter for my notifications, e.g. notify me when there is Motion in my garage when nobody is home (have all my sensor notifications set up that way for the case of home intrusions otherwise it’s annoying).
I have a nanny that comes 6/7 days of the week. She is labeled as a user in my Homekit app and I made a few automations to fire when she leaves and arrives at my house, other than the sensor notifications for when “nobody is home.”
The automations never worked properly for her and neither did the sensor notifications, but they did work for other users of my home (my wife and I).
I checked the privacy settings on her iPhone (with her approval of course) and it seemed like it was fine. Settings>Privacy>Location Services>Home>While Using the App (App explanation: “Home uses your location to let you set up accessory automations like turning off the lights when you leave your house.”
Still didn’t work and it was driving me crazy and I must’ve checked her phone a dozen more times to see if this was still enabled. It was for my wife.
However, I checked one more time today and noticed that after clicking on Location Services, there is another option that says “Share My Location”. I always thought this was just for “Find My Friends” which I use with my wife. But if you click on it, the caption also says “... and use automations in the Home App.” This was checked on “iPhone” and not “From this Device.” Didn’t know that was used for HomeKit also.
So apparently, it was still trying to use “Share My Location” from her old iPhone and hence why none of the automations and notifications were working properly. HomeKit geofence wasn’t able to “see” her correct location at my house.
Basically, if the notifications and automations aren’t working properly, check the privacy, Home app and share my location settings for all users of your Home and make sure they’re set accordingly. Working the way it should now... so far (knocks on wood)