Hi XD
I've noticed this as well. If I recall, this transpires when that certain person hasn't been on, well, to say the least, in a bit XD. It will black out the avatar. Those pupils iris eye white stuff might be an internal error. It is freaky, but nothing major. It is a bug, in essence, so this is in the right section ;P. Normally black avatars occur after about 6 months? I have no clue what so ever. Note that people can submit there OWN photos for there avatar, but it most be mod approved. This may be part of it as well, but I'm not certain.
balance