Yeah, dameruth is right. They've decentralized the icon serving which has caused mislabeling of icons in the database (there was an lj post about it a couple of weeks ago). So you'll see the wrong one and some people looking at your post will also see the wrong one but other people will see the right one. I've had it happen a couple of times that I know of. The last time it happened I commented that my icon was wrong and half the people said 'huh?' and the other half agreed with me.