I have correctly configured Facebook social login alongside Google+ login. Whereas Google+ works well, Facebook requires the user to reload the page. 

I do have an alternative login form for my website and that works fine with Facebook login using the same APP.

But the login on wpDiscuz acts like it's not working. But when you refresh the page, you find the user is logged in. 

Since Google+ works, that means something is wrong somewhere with the Facebook login. You can test it out here. 

https://kicheny.com/premium-lovely-responsive-design-illustrations/

Test both Facebook and Google on wpDiscuz and also, check the theme's default login top right section on the menu header.