2 Wierd Iphone problems. Anyone can help? :)

[Cryonic]

Problem 1. I managed to turn off the notifications in lock screen mode when there is a new facebook IM but it keeps turning itself on again.

Problem 2. Using Facebook messenger, on one of the persons in the list I can only scroll back exactly the last 21 messages.

[Mimir]

I have two solutions below:

1.) Delete Facebook
2.) Go into Notifications, select Facebook. Now toggle the Allow Notifications to off, Badge App Icon to off, Show on Lock Screen to off, Alert style to None. If that doesn't work, delete the application and re-download. If that doesn't work, it's likely a bug that you should report.