In the administration area in the Social Sharing tab there are the social site tick boxes: Facebook, Twitter, Google etc

When I uncheck the boxes and save the configuration and then go back to the settings that have been reset and are checked again.

If I go to the database table and remove: fblike,tweet,googleplus,addthis
then the config is fine and when I go back to the Social Sharing tab they are all unchecked. However, if I make any other changes on any other tabs and resave then the boxes are checked once again.

Is there a default config file somewhere that sets these social sharing text boxes?