Google Toolbar bug or Page rank Bug?

I found an interesting behaviour in the Page rank feature of the google toolbar in IE. For example when I view this blog with the fully qualified URL i.e. http://www.desigeek.com/weblog/amit my page rank shows up as 7/10 and when I view it using the abbreviated URL http://desigeek.com/weblog/amit (no www.) then it shows up as 3/7. You can see both the screen shots <strong>here</strong> and <strong>here</strong> showing this behaviour.

My question is, has anyone else also noticed this? Is this a bug or a feature? If its a bug is it in the Toolbar or google’s page rank? One would suspect the latter, as the toolbar would “call home” to get the rank for the URL to be displayed. What do you think?