Facebook and Twitter Login not working when using a shortcode


I'm using the [eab_single] shortcode to display an Event in an article, if you click "I'm attending" or other response, it takes you to the wordpress login page, but if you visit the actual event page, it asks you to choose if you want to login with facebook / twitter etc...

Is there a way round this, or is this a limitation of the shortcode? (I want people to be able to register with twitter and facebook etc)

Thanks, Chris.