google shows older page in cache

[efirkey]

I have pages that are several years old that have been indexed by google. I recently made changes to these pages and within a couple days google had these pages reindexed with high rankings.

However a few days later they revert back to showing older versions of the page that don't rank as high. Then months later they finally will update with the newer version of the page.

Why does it show up immediately then drop out not to get pushed up permantly for a few months? Is google a tease?

I've seen them do this on many occasions. It's like a sandbox for refreshed pages. Is this on purpose so that we don't constantly tweak our pages?

[g1smd]

I assume that the "old version" is marked as a Supplemental Result and the "new version" is not, whenever either one appears in the SERPs.

If so, then that is how Google works for the last two years. They keep an old copy as well as the new.

[efirkey]

but why do they show the old copy? and you are right about the supplemental.

[g1smd]

If a page showed in the results today, but then tomorrow the page or the site ceased to exist, then Google tries to do surfers a favour by caching the page for a year or two after it has gone.

They also hold on to the previous version of a page when the page is merely updated for much the same reasons. They can also use that old copy for various anti-spam and duplicate content functions.