Check your microphone privileges on all social media, and apps like YouTube, and make sure that the mic permission is set to "Only while using the app". Most of those apps will cache small voice recordings and forward them to the apps and services. That's how it customizes its ads to you. It's also why people are paranoid about their devices "listening" to them.
When Facebook Messenger was first released, it asked for permissions to mic, cam, phone, contacts, and photos. A video immediately went viral and hit most national news outlets of a man ranting about Facebook stealing our data and spying on us. It can and probably does get used that way, but that was never the intent. It was literally the app asking your permission to do those things to make your life easier. So all of those functions could be used through just Messenger.
However, if you don't want extra data and input saved, change your permissions for the mic from "always", to "only while using..." Should clear that issue up.