That's exactly what it's supposed to do. The Facebook app is no longer fully supported.
As of March 31st, 2016 BlackBerry smartphone users will have to perform an update for the BlackBerry Facebook application in order to continue using Facebook. The current BlackBerry Facebook application will cease to work on BlackBerry smartphones running BlackBerry 10 and BlackBerry OS versions 7.1 and earlier.
Those wishing to continue using Facebook are encouraged to move to the web-based experience which will provide the most feature rich alternative. To transition to the web based experience, users should visit BlackBerry World on their device and apply the available update for the Facebook application.Facebook for BlackBerry 10 has been updated, but you're not going to like it | MobiFAQ.com