Google Assistant bug is draining the battery on Android phones
“Wondering if anyone else had this experience where the Google app stays active if you say “Hey Google” and your request was answered by another Home device (i.e., you say “Hey Google,” phone and Home device both pick it up, but the request is handled by the Home device). Quite a few times, I’ve found that my phone battery is completely drained a few hours later, with the Google app being active the whole time, and I think it’s because Assistant on the phone was left hanging. I can’t be sure though, and I was wondering if this was something other people had noticed, and if there’s a solution.”-u/qdatk, Reddit
The bug doesn’t seem to be a problem every time two Assistant-enabled devices are close enough for both to hear the hotword. But you don’t want to put yourself in a situation where you need the phone and the battery has been unknowingly depleted. So until Google comes up with a way to exterminate this bug, it is best to check your phone every time you activate Google Assistant on your Google Home/Nest device. You need to check especially if the phone is inside your pants pocket or sitting on a table where you might not notice that the Assistant is stuck in listening mode.