_confg.yml changes are not picked when you deploy to github pages using
rake generate deploy
rake preview running another tab, it was started with older version of the
_confg.yml. This was also generating the html files into same
_deploy folder. Hence when you run
rake generate deploy, it was pushing html generated by
rake preview task.
rake generate deploy, make sure you are not running
rake preview or
rake watch in any window or tab.