Time-out in interface loading read items?

When loading items and searching for next un-read in feeds with a large number of read items, interface seems to time out and skip to next feed.

Example is http://www.ritholtz.com/blog which is quite prolific and because I usually prefer to still see read items it tries to load them all. But before it gets to the next un-read item it seems to hit some kind of time-out and then skips to the next feed with un-read items.