When i log in via facebook, my index url changes and adds a #_=_ to my url which then doesnt show any of my articles on my homepage. im not sure why it does this but if i delete what it added to the end of my url all the articles reappear.
That mostly sounds like an issue with your article list page. This is something that FB is documented to add. It may be possible to remove it with some amount of modification, but I'm not sure what would be required.
@Mike after upgrading to 1.3.4 I am having this same problem, but logging into xenForo.. It shows the user quick then refreshes as logged out again. I have disabled all addons and using the default skin with same result still. Even tried deleting .htaccess and turning off friendly url's.. no dice.