A hardware fault in a Google Home Mini review unit provided to Android Police continuously recorded all audio around it and sent it to Google’s servers.
Google devices like the Home Mini typically wait for the phrase “OK Google” before beginning to record and then sending audio to Google’s servers for processing.
Upon reporting the issue to Google, the company discovered the speaker’s touch control sensor was malfunctioning.
Under normal circumstances, you can long press the touch control to speak a command. Following the report, Google has temporarily disabled the feature.