He's since changed his avatar and to my surprise my post "updated" its self to reflect this.
Not sure if bug or feature? I can see it either way really.
As a bug, we could argue that it doesn't reflect the content I posted any more & of course, what would happen if I could no longer edit my post after X time and that person tries to change their avatar.
I could also argue this as a feature, because if I was talking about X person in a post and they changed their avatar, the content would still remain relevant.