Something on stock Android phones is always listening though. I had a similar experience as OP where I had an IRL conversation once with my son about a product I don't normally talk about. My phone was unused & "asleep" nearby. An hour later at work I was inundated with ads for said product all over the internet in my Chrome browser on my work computer. It was way too heavy handed to be a coincidence. The phone had listened to our conversation.
(That day marked the first on my journey to de-Google and take serious steps preserve my privacy online)