HomePod Siri incorrectly hands-off HomeKit request to iPhone, resulting in weird iPhone response

Since the release of iOS 13, Siri frequently misidentifies whether I am talking to my HomePod or my iPhone when making a HomeKit request such as "Turn on the lights". This happens most often when my iPhone is set near the HomePod. It doesn't matter whether or not I have touched the phone recently, or if the screen is lit up/on or not. The HomePod definitely hears me, but instead hands off the request to the iPhone, at which point I get the response on my iPhone shown below. My iPhone most certainly has a passcode set, AND I use FaceID.