I'm seeing a stranger in my messenger's contacts

Question

I'm seeing a stranger in messenger contacts, that are apparently from phone contacts, is this a glitch or something?

Answer 1

That's probably because Messenger is also an SMS client, so you can use it to message people in your phone's contacts even if they're not connected to you at all on FB.

At some point in the past, you've authorized Messenger to access your contacts; that access can be revoked if you'd prefer, but how will depend on which platform (iOS vs. Android) you're using.