Can you give us a link to a post where the shortcode is failing to work?
Also, try deactivating all plugins. If that resolves the issue, reactivate each one individually until you find the cause.
If that does not resolve the issue, try switching to the Twenty Fourteen theme to rule-out a theme-specific issue (theme functions can interfere like plugins).
it is failing everywhere on FrescoVideos.com
the really big image on the top of the page is set as Featured Image and theme is handling that Pinto from Themebeans.com
all the rest of the images on any of the page, including front page should have captions
The theme developer insists that his theme is totally compatible to the latest WP release.
I did the “disable plugins” before posting here – did not solve the problem.
I am afraid to switching the theme – it is live website and I don’t want to risk breaking the layout completely and then not being able to get it back…
is there a special section that handles that particular shortcode? ore better question would be what will strip it (aka if I disable a plugin that uses own shortcode, the page prints the html of it) This one strips it completely like it was never there?
That particular shortcode is built into WordPress. Unless overridden by a plugin or theme, it will work.
Since you ruled out plugins, the only way to know if your theme is overriding it or not is to switch to the Twenty Fourteen theme temporarily to see if you still have the problem. It won’t damage your current theme.