i have recently change design of my site google show cached page from 30 may with my new design all is ok but the 2 june i see cached page from 26may with my old template and today my cached page is always from 26 may what the problem? 30 day ago google update my cached page everyday i have recently add a geo ip to my shop its the problem maybe?
you can help google to keep on crawling and indexing by continues gathering of links.. which can also help your cache page get updated..
Sometimes Google shows the old version of the page even if the new page has been cached. Try to get you website crawled frequently this will help in removing the old version from Google database quickly.
i had a same problem with my blog but give some time to Google it definitely crawled your site again and you can see the cached page of your site
This is pretty common since most of new change, especially whole theme change will cause a small delay with indexing / caching. This could be back to normal around 1-2 weeks.
May be Google Displays based on the DB availability and server load They may spread your cache in Different DB at different location and may choose one to display
The reason for the pages dropping on the serps is that those pages are decached and so other pages are being returned for those searches that are not as well optimized, and dont have specific links for that phrase.