If there is something wrong with gravater what do you expect this site to do about it? it's an entirely separate site.
though it's most likely to be caching.
"I changed my gravatar, but I still see my old one on sites!
We cache your gravatars for periods of time, which means that your new gravatar will take effect after the old one expires from the cache. The reason we do this is to be able to serve your (and indeed everybody’s) gravatar images much more quickly and reliably."
http://en.gravatar.com/site/faq/#answer-1-2