Why notification is saying my Facebook name messaging me when it's someone else messaging me?

So, out of nowhere, when I get notifications about someone messaging me on Facebook Messenger, it says my Facebook name is messaging me instead of the other user. But when I go to the app, it says their correct name as the person who messaged me. But when they come into my phone, it shows my Facebook name, like I messaged myself but it's them messaging me. Could that possibly be me being hacked or is it just a system malfunction?