A question for IT Nerds about remote activation of Google Assistant

recently I had a very privat conversation with a good friend

in my livingroom.

Just after my friend shared the very privat fact,

that he occasionally suffers from incontinence,

my google assistant app activated itself

and a female voice said : "EMBERASSING ! "

Non of us two mentioned the phrase : ok google ,

so I guess someone was listening the conversation

and had the knowledge to remote control the app.


Is there anybody reading this,

who can explain, how this unwanted feedback

could have been activated ?