Facebook message notification showing blank message Since I updated the system to 10.11.5, the Facebook message notification is not showing message text.


Is this a bug in this software upgrade of OSX?
This change is not a result of your specific OS X version. The change is on the server end by Facebook as they control what data to send to your Mac and the reason the text isn't showing is the text is no longer sent. 

You might contact Facebook support to see if they are aware of this change - perhaps it's unintentional or you can so figure the web app to send the extra data to your browser.