Having just upgraded to 3.4, I've discovered that many of my photo uploads are no longer available properly. For some reason it appears WP is no longer able to link a media upload post with the meta data (stuff like thumbnail paths, EXIF, etc.). Since not all of my photos are missing, I've tried comparing the database entries for both posts and have not found any differences.
Has anyone else found this? I'm digging through the database but so far have come up empty.