I like to use the Threaded View Mode. In most cases it works correctly. There are a few threads where it refuses to work. When I go to one of the problem threads the first post will correctly be displayed but the list of posts in the upper window is blank. Pressing 'next' or 'prev' does nothing. I can, however, switch to hybrid or straight view and see all the posts. Switching back to the theaded mode produces the same faulty result.
is one of the problem threads. There are others I've seen but haven't saved the link. I don't think the number or posts or length of the the thread is a factor. I have been able to view some very lengthy threads in the "threaded view" mode.