All accordions are automatically cached the first time when they're viewed by a visitor, so next time when someone visits the page, the accordion will be served from the cache. This mechanism saves processing time and is especially useful when loading content from posts or external services.
When an accordion is updated in the admin area, the cached version of the accordion will be deleted. Also, you can deleted all cached accordions from within the Grid Accordion -> Plugin Settings page, by clicking on the Clear all cache now button.
If you want to not cache an accordion, you can set the allow_cache attribute to false, in the shortcode:
[grid_accordion id="3" allow_cache="false"]