https://techcrunch.com/2017/10/10/google-home-mini-recorded-24-7-androidpolice/

The idea of inviting an always-on recording device into our bedrooms would have once seemed beyond creepy but now most consumers hardly give it a second thought.

As Android Police reports, a small number of Google Home Mini review units given to tech reviewers malfunctioned, persistently recording audio in the background without being activated by a hotword. The Home Mini units gave no indication they were recording beyond silently flashing their four display lights — a notification that you’d only notice if you were looking directly at the device.