I have also not encountered the credentials going stale issue. It might be worth clearing your browser cache (remember when we had to do that to fix ANYTHING? I have barely needed to do that in the last year or so, but it comes up occasionally).
Re navigating, the list of posts works ok - you can press H to jump from one post to the next. When you actually go into a post, the UI breaks down a bit. Mostly because (for me at least), n doesn't seem to work to jump to the next non-linked text where it should (as in the body of motobojo's post, or any replies). The "Skip to content" button also doesn't seem to work - it comes up as the first item on the page, but you can't activate it?