Since I upgraded my Torch to OS 18.104.22.1680 I have been having this issue where I get phantom Facebook unread messages. These messages are nowhere to be found when I look in the messages folder in the Facebook app. I try marking all my messages in the messages app as read and it still does not go away. It got really frustrating so I took the issue to Twitter and it seems like I am not the only one though not everybody is having the issue.
After trying to fix it multiple ways I finally found a fix that works for me. I just clicked on the “Activity Feed” right where the Facebook notification is (does anybody actually use this delayed activity feed???) and it turns out it shows the unread Facebook message. I checked the Facebook app again and that exact message was marked as “read” in the app which confuses the hell out of me. I ended up just going to that message through the activity feed and it went away.
Problem solved… for now. Let me know if it works for you!