Question about Google Toolbar and Pagerank

So, I’ve been checking the inbound links on one of my sites, and I have noticed that when I click them going from the linking site to my own the page rank on my toolbar goes from whatever it was on the previous page to nothing (“No page rank available”) on my own site. If I go straight to my own site, however, the page rank is where it should be. I checked the source code on the site with inbound links, and didn’t spot any signs of a No Follow. Would this be a hiccup on the part of the toolbar, or could there be something going on inhibiting page rank being transferred in this case?

The page rank belongs to the page - how you display the page doesn’t matter. Therefore it is a glitch in the toolbar processing.