When I'm in my Gmail inbox, I click the "Older"/"Newer" arrows in the upper-right of Gmail, in order to look at emails further back than 50, but nothing happens. It just says "loading" at the top for a few seconds, and it says "51-100 of 21749" but it still shows me the first page of emails.
I've tried this on Opera, Chrome, and IE, in incognito mode, at home, and at work, and it works the same in each case.
I've included a screenshot to demonstrate this. I've censored the email subjects, but you can still see that the emails are the same by the dates on the right, which remain the same whether I'm looking at emails 1-50, or 51-100.