I had this issue as well after upgrading WordPress versions (currently at 4.2.2). I noticed that my fancybox’d gallery images had no title/description, however my fancybox’d images did. Browsing my page source indicated that the gallery images did not have any title set, only alt, vs my images that had both set.
I edited this plugin’s source, line 229:
var title = jQuery(this).children(“img”).attr(“title”);
to
var title = jQuery(this).children(“img”).attr(“alt”);
and my fancybox’d gallery images are now showing descriptions again.
