We often get false positives as well. I've wished there were some way to signal a false positive to the device after Siri is activated, like "Siri, I didn't ask for you," to help it learn/train it. Not sure how feasible such a function would be, but I imagine it would be helpful feedback down the line on the engineering end. Anything to reduce the false positives would be great as they are a) a nuisance and b) further confirmation to friends/family who witness it, that we've made a mistake allowing a "surveillance" device in our home.

I would guess that they are inferring this based on whether the device gets another request in rapid succession.

Have you noticed that certain queries that used to work have stopped giving you the expected response?

I've started noticing more false positives since iOS 12 launched, and there's a couple requests that now don't give me the expected response. The most annoying issue happens to be requesting Siri to set an alarm. I'll ask: "Hey Siri, turn on my 6:15am alarm." to which she'll respond, "Which alarm do you want to turn on..." and then list all the different alarms I've set on the HomePod.

This all changed with iOS 12, and I wonder if I should reach out to Apple or just live with it and hope it improves with a software update??

If you think about what you asked Siri it's a sensible response.

You didn't ask her to set an alarm for 6:15am. You asked her to turn on an existing 6:15am alarm.

Which since I am assuming it didn't exist Siri asked what others you did want to turn on.

Late response, but here's the thing...that alarm does exist and is listed off when Siri goes through all the existing alarm options that can be turned on...

Haven't noticed certain commands no longer working, personally.