We were migrating some post and sections from our database, to another site last night. During that process, it appears that some members avatars were broken. Everything else is fine, and nothing was lost.
I'm not sure why some of the avatars were broken, and there doesn't appear to be any rhyme or reason to what members were or were not affected. Unfortunately, if your avatar was broken, you'll need to add it back to your account yourself. I would do it for you, but it's not a matter of the links being broken, the files themselves are no longer on our server.