Only the availability data on the Search page is not real-time - it is cached for the whole day, once someone gets the same. This is to keep the search pages as fast and responsive as possible (fetching avl data is a very slow process). The search page availability data is to give an overall big picture of what the availability is like. However, it is still as of the same day, not before.
All other data on this site is real time. Availability data on the individual train pages, pnr, running status, etc. are all real time. Please let us know any specific cases of other "cached" data. Thanks.