For some reason certain pages add the "fb_xd_fragment" parameter to pages.
This is caused by the facebook like button bug, apparently the solution is to rollback to the previous facebook SDK.
Since my site is set up in htaccess not to disallow any parameters with "?", this is what happens:
1) normal page:
2) page that got additional parameter
shows blank (but with 200)
I've run this in Google: "mysite.com"+"fb_xd_fragment" and it results in 0.
I guess I managed to avoid a catastrophe and have the majority of my pages duplicated.
I rolled back to old facebook SDK (using iFrame).
My question - should I keep everything as it is now, or should I take further steps? Like create redirects from fb_xd_fragment to normal pages?
I was tempted to do this, but then remembered that it is not smart to fix something that hasn't been broken :P