I think some pages are generated statically and expire. Why the login/logout pages "expire", I can't really guess at. Wow, not sure why this is so deserving of

I think some pages are generated statically and expire. Why the login/logout pages "expire", I can't really guess at. Wow, not sure why this is so deserving of downvotes. Trying to find a source, but I thought there was a previous discussion of many HN pages being statically generated and served quickly with links that expire after a certain time (or become invalid because of what may happen on the server side of things). But oh well.