A while back, when the site was rather bogging down, pg made some changes to memory management (as I vaguely recall from one of his comments posted at the time). I believe part of this is more aggressive discarding of memory, and that part of the result was to succeed, or fail, more quickly without progressively tying up the server.

So, overall the server works better. When there's load, part of this include bailing sooner on your troublesome request. ;-)

In your case, this may include no longer having memory/context for stale pagination links. I deal with this by using a browser extension to load several pages of links at once. (Without a browser extension, one can achieve the same results by opening those links manually in new tabs and then working one's way through those tabs at one's leisure. I'd advise not overdoing this, though; no need to burden the server with requests you will seldom/never use.)

(I may be wrong as to the memory management. Again, this is just my vague understanding/recollection.)