Not sure what is happening, but many times I rate a site using my toolbar, but after submitting, SU says that there is no record of the page. Furthermore, sometimes i see friends who have favorited my site on their SU profile. But when I look at the SU page for my site, it doesn't register my friend's nick anywhere. Can someone explain what is going on??
I think I've seen the same thing, usually I just ignore it and check back later, hoping it was a glitch. One thing that can happen is that if people choose to keep their stumbles private (just between friends,) you'll see the review on their profile, but you won't see it on the actual review page.