Edit: I apologize, I changed a different setting and I now notice the banner saying it may take up to 30 minutes to reflect! Plus the STICKY THREAD for general bugs.

I'm not for sure this is unintended functionality, but if you change your avatar, previous posts will display the old avatar unless you edit the post.

yep - sorry for the confusion there. our caching strategy for posts is pretty aggressive, and updating your avatar will not clear an already cached page of posts. that's why you'll see your avatar appear correctly in newly viewed threads, but not ones already cached by out backend service.